I'm squarely in the "beyond" cohort and, barring major calamity, likely to hit the upper end of this range sometime in the next 10 years, just by not drastically inflating my lifestyle and letting my little green employees recruit more of their friends.
There's a recurring theme earlier in this thread of "Silicon Valley would mess up all of this for an ordinary worker." Silicon Valley's housing prices are outrageous precisely because so many people here can make enough to afford houses this expensive. Yes, there is too little supply, and it's gotten worse in that respect in the last decade. Yes, we have a lot to answer for when it comes to the gaping wealth inequality. That's already a few other threads, mostly in Off Topic.
For us, though, living in Silicon Valley is how we've been this successful, not why we need to be.
Our net worth in this VHCOL area is roughly divided in three, between a paid-off house (bought a little over 20 years ago for something like 1/3 to 1/4 of what I might be able to get for it with the right upgrades), the amount we've saved and invested from our two engineering salaries, and the value of some well-timed stock compensation in what has turned out to be a successful company.
We're both still a bit under 50 and both born mustachians, if there is such a thing. I haven't done the numbers in a few years, but I think our baseline burn rate in years when nothing special is happening is somewhere in the $30–$40k range. House upgrades or a new car will change that number, of course, but with a little care the upgrades should last for many years, while the bills will be one-and-done.
After I pointed out that the job market had heated up during the years I stayed at the same job, a long-ago manager delivered the largest percentage raise I've ever gotten, with a comment, "I suppose we shouldn't expect you to live like a college student forever." I think DH and I both like it that way, though. We still ride our bikes most places. We cook food from the store and the garden, making extra for leftovers for the next day's lunch. I don't generally wear it to work, but I have apparel older than some of my coworkers. We still make active use of our library cards.
DH and I started pondering our next overseas trip, and I looked up what an upgrade would cost. An $800 plane ticket seems to turn into a ~$4500 business class ticket, and even though he could certainly do with the additional legroom, neither of us cares that much. We
will spend an extra few hundred on airfare to reduce logistics. We'll opt for a direct flight instead of layovers that are too long or too short or that add hours on a plane to go through a hub that's not really on the way. We'll pay a little more to avoid arrivals and departures in the wee hours when nobody, including ourselves, is awake and open for business. It's still a modern miracle that we can, if we want, pay some money, spend a day trudging through airports, and wake up in Copenhagen tomorrow.
What
@Metalcat said about 5x the price not resulting in 5x the value is an understanding that seems to be built into us. It probably helps that DH and I are introverts with little to no interest in status.* The eventual car upgrade will come when the old one ceases to meet our needs or to be economical to maintain, not when we're the only ones on our street with a car that old.
Maybe it's because we're engineers, but the $6000 smart fridge just looks like a mess of unnecessary electronics that add nothing to the basic task of keeping food cold. They also pose a security risk, and they're sure to be obsolete in something less than the 20 years we've had our current fridge so far.
The frugality also seems to help with stealth wealth. Some of my friends are struggling to varying degrees, and "I could spend circles around you" is not something they need to be reminded of, even if they kind of already know. I suspect the older car helps communicate that there's nothing too fancy inside to steal, either.
The one place it's visible is to the institutions. We have whatever the executive status is at a major brokerage, and they'd just love to help us manage our money. I've gotten cold emails from someone offering investment opportunities in some kind of early stage VC fund. I presume they either figured that anyone who's been at my company a certain length of time is likely to have enough stock to qualify as an accredited investor, or they paid for a high-NW mailing list from someone who did. That kind of stuff feels icky, but it's easy to ignore email.
Another thing
@Metalcat got very right, earlier in the thread, is that philanthropy gets more challenging when the numbers start to get bigger. Somewhere between the odd change that you drop in the fishbowl and numbers with commas, it starts to be worth asking if an organization is delivering the results it promises and if that result is actually worth advancing.
House the homeless? Yes, great! House the homeless with a bunch of condescending religious values that are enforced by separating them from their partners as a condition of that housing? And then blame them for not accepting the "help"? No, isn't there someone else who doesn't do that? How do you tell?
See also: reforestation efforts that plant a monoculture of the wrong trees in the wrong places, use up scarce water, fail to keep them alive, and/or sell carbon offsets to polluters for mitigations that look good on paper but mean nothing in real life. If you decide to let Givewell or somebody else curate and vet, do you trust the reviewers?
That eighth and leftmost digit, if/when it happens for us, will likely happen due to compounding and momentum more than any further additions from earned income. So what's it all for? I don't entirely know. RE, yes, probably, although I can't claim to know why yet. It feels pretty weird to think about, and neither of us is sure what we'll do with our time. Maybe that's the kind of thing we'll have to live to find out.
To circle back to the topic of this thread, is $10M better? It's certainly better than any version of having to decide what basic things to do without to scrape by. I may have some exploring to do, to figure out what really feels like purpose to me. I'm fairly sure neither golf nor boat ownership will be involved in the chapters of my story still to come.
*At least not traditional, economic status. Nerd status may be another matter.