I checked on the costs for one of my state's public universities for a 4 year undergraduate degree.
Assumptions:
Graduates in 4 years, Fall and spring semesters. No summer school.
In state tuition because out of state tuition is insanely high.
A four year degree would run $28,000 in tuition and fees. That's less than the cost of a median-priced new car in the USA.
Very affordable. Books, of course, would be extra. Books could be covered by a part time, 16 hr a week job during the school year and during the summer. If a university isn't within commuting distance, then room and board for 8 semesters in a dorm with a meal plan would run another $37,000.
That's definitely payable if someone gets a decent job after college.
Throw in a 3 years working before they go off to college at minimum wage, after taxes, and you could shave over $15,000 off that college bill. Take a bunch of AP courses or college courses in high school and you could shave 1/8th to 1/4th off the overall bill. If you qualify for grants or scholarships, it's even better.
College is affordable if people make good choices.
Now, if the student instead:
1) Fails classes because they don't do their work in high school or college and has to pay to take them again, or
2) Takes the wrong classes because they were too lazy or inattentive to read the damn catalog and make sure they are taking the right ones, or
3) Changes their major late in the game so they have to take additional classes to graduate, or
4) Doesn't pay attention to when those final senior-level classes are offered and has to take an extra semester or two just to take one or two classes, or
5) Goes to an out of state university "for the experience" instead of there being a measurable, financially rewarding payback for doing so, or
6) Lives in a nice apartment with a nice car and eats in restaurants all the time and drinks like a fish...
...then college may become damned expensive.
Personally, I would work an extra year and toss all my net income from my salary into the college savings pile. Then let it grow and teach my kid to start working in high school. It will serve them well to learn that lesson. Between those two actions your kid will but $15,000 skin in the game and you'll put in another [however much you earn after taxes]. $30,000 from you would get them into nearly free territory. 2 kids? You would need $60,000 from you and 2x$15,000 from them.
Of course, if you follow the advice to not pay off your mortgage quite so early and invest the difference, that investment growth might very well reduce that 1 or 2 years extra to nothing.