I'm still confused about your argument. You point out that a small number of hypothetical people and a very, very small number of actual people use smart phones for these super-important uses
I wouldn't consider millions of people to be a "small" number, and they aren't hypothetical. They are very real.
(which, as you pointed out, could often easily be replaced with other technology, and still needs to be supplemented even in these cases),
The thing with the other technology that could replace what's provided by cellular phones is... it requires money and resources
. Money and resources are the exact things you're guaranteed not to have if you, say, grew up in foster care and aged out of the system. According to childrensrights.org, 20,000 teens age out of the system every year in the United States. When this occurs, they do not have driver's licenses, state ID, a bank account, or (in most cases) a high school diploma. They most assuredly do not have a home to live in that has a landline. Nor, in most cases, do they have access to Internet resources through work. They have a couple bins of cheap clothing and maybe a photo album.
and only then in exceptional and complex circumstances and then equate smart phones to public septic systems and reliable electric utilities?
Some of the SERVICES PROVIDED by smart phones (I shouted those key words because you don't seem to be picking up on them) are real-time communication, navigation aid, directory assistance, photography, mobile banking, bus route lookup, calculators, flashlights, translation, audible reading for the blind, Internet access for online job applications and education initiatives, point-of-sale transactions, note taking, bill payment, alarm clocks, closed captioning and even voice transcription for the profoundly Deaf, and more. Is it possible to replace all of these things with other kinds of technology? Yes, it's just going to cost one heck of a lot more and require infrastructure a lot of people don't have. The fact a smart phone is compact and portable enough to be safely carried around is a huge asset.
I think that's all that needs to be pointed out: the general public would not be measurably worse off without smart phones. The general public would be measurably worse off without electricity or running water or working sewage systems in their communities. The exceptions clearly prove the rule. A non-zero number of people need electric scooters to function in society; many people would use them to greatly enhance their daily lives and be more efficient with their time; we don't suggest that electric scooters bring as much good to society as running water or that they should be regulated and mandated to ensure access to all persons as a matter of mass societal benefit. An $40 dumb phone? Maybe. A $600+ smart phone with internet access plan? No, not hardly.
Never once have I recommended providing smart phones as regulated, mandated services to the general public. That's a straw man argument.
To a quadriplegic, a motorized wheelchair is at least as important as plumbing or running water. That quadriplegic, like it or not, is a member of society. As a society, we have a vested interest in making sure our weakest members don't starve to death... and in the meantime, the quadriplegic may just happen to be Stephen freaking Hawking.
I've argued in favor of providing smart phones to people who need the services provided by those devices to live independently and to have a reasonably productive life, and that do not have access to those services through other means. The "dumb phone" you're suggesting might have a tip calculator, phone connectivity, and maybe an alarm clock but it's not going to be able to help someone apply for jobs, read someone else's words spoken into a microphone when that person doesn't speak sign language, or work through public transit schedules. It's just not powerful enough to help a Deaf person ask for, and get, intelligible directions from a stranger who doesn't use sign language.
I'm trying to drill down to the core of what's bugging me about your argument. I've boldfaced a word in your last paragraph that I think provides a possible explanation. You're coming across as though you really, truly, honestly believe that "all persons" are as able-bodied and otherwise privileged as you are. That's flabbergasting me because it's so far from reality that I'm reacting emotionally.
Here are some statistics. 50% of all humans are on the left side of the bell curve, and more than 15% of them are at least one sigma out. This isn't something I'm making up, it's a basic statistical fact. The US Census Bureau at www.census.gov/popclock
lists the US population at 323,148,587. Mathematically, 15% of that works out to 48,472,288 people with a measurable IQ of less than 85. (For reference, that's more than the entire population of Canada.) The people in this set have an IQ too low to qualify for military enlistment under most circumstances. And, that doesn't count people who test within or above the normal range but are limited due to physical disability.
The more than 48 million people I described above can generally not be taught to program computers or fly aircraft. You can spend a lot of extra time and resources trying to train or educate them but there's going to be a level beyond which you get diminishing returns. Unskilled labor or semi-skilled labor is going to be the most they can manage, and many of them aren't educable to the point where they can pass the written test for a driver's license to operate a motor vehicle. Yet they're still not far enough on that left side of the bell curve to be eligible for social assistance, so they've got to work and get by as well as they are able. It's brutal because some of the most basic things take them longer. Stuff you or I could do in our heads, like calculating a tip, remembering what time to leave the house in the morning, or understanding whether or not we have enough money for groceries, really is impossible for them without some kind of electronic assistance. Worse still, the kind of jobs they can get don't have much in terms of benefits, are likely to be part-time, and they go away often.
Technology won't help people at the extreme left end of the bell curve, two or three sigmas out. But between the first and second standard deviation there's a sizable group of people who, with help from technology, can become more independent and can take responsibility for key aspects of their own care. Throwing technology at the problem is far, far cheaper than institutionalizing those individuals or letting them starve or live under bridges. When an individual is able to, say, hold down a job and pay for at least some of his or her necessities, or pull his or her own weight in a household, that individual becomes an asset to a family instead of a burden. The odds of him or her becoming homeless in the first place therefore go down.
That's why, for the people who can be helped with, say, a motorized wheelchair or a phone with Internet access, I say: sure, let's hand it out and maybe buy fewer bridges to nowhere. It doesn't have to be a top-of-the-line phone, but the unlimited bandwidth sounds to me like a reasonable idea because it allows for GPS navigation and also online education programs. I say that even knowing that at least some of the people who receive the phones aren't going to have the slightest desire to better their situation, and will sell the phones for crack or use them to make wheelchair porn.
People for whom smart phones are a luxury (and by that I mean able-bodied people who graduate from normal high school programs) are still more than capable of buying what they want and paying for it themselves.