Teacher here. There are plenty of reasons why I didn't have kids, but the low pay of my chosen career is one of them, I guess. (I also refuse to come home and work a second shift, but that's another story). Some people go into it knowing the have a spouse with a more substantial paycheck, and do fine. A lot of teachers simply live very frugally--lots of my colleagues drive older cars, forego spendier vacations, and budget very carefully.
"The 50s" wasn't an era of perfect education (US never had one of those in my own opinion). Schools from that era look good in retrospect, but part of that is because expectations were different...and often not in a good way.
Schools were cheaper to run for a few reasons:
1. student transportation/school buses weren't as widespread, and were non-existent prior to WW2. Walking a few miles to school was considered normal. So no buses to pay for.
2. overtly screwing over students of color was considered a normal practice. Schools for black kids were a joke. The money went to white schools. This was exacerbated when the suburbs were designed (look up black/red line neighborhoods sometime...suburbs were designed to keep brown people out).
3. students who weren't achieving were encouraged to drop out of school (even if they were younger than 16), and lots of poor families that moved a lot simply didn't send their kids to school. Data on student achievement were not tracked or analyzed, so schools didn't have too many hard numbers on how their students were really doing over all.
4. special ed as we know it didn't really exist. There were no laws requiring schools to serve students with disabilities of any sort (those laws didn't come along until 1976). SpEd services are fuckin' expensive.
5. in some states (such as CA), the definition of "public education" means that the parents don't have to lift a finger financially. Schools provide EVERTHING, right down to pencils and paper. Schools cannot require parents to contribute in any way to their kids' education. So that's more money.
6. there were a ton of schools built in the 50s for sure, because of all the baby boomers flowing into the system. (the demand for teachers was so huge that in some cases you could teach elementary school with only an associates degree, which meant there were 19 year olds teaching in some cases!) A lot of the buildings built back then are simply aging out and have had band-aid maintenance for decades. Schools also have to be larger now, because of all those intervention and SpEd programs. So, more structure to maintain.
7. Staffing a building was simpler. Teachers, principal, secretary, some custodians. Slightly larger staff for specialized classes in high school. But no counselors, school psychs, reading/math intervention teachers, SpEd teachers, instructional coaches, speech therapists, occupational therapists, etc. Fewer people to pay.
So there's some food for thought.
As for the tax idea...I don't know enough about it to say one way or the other. I do think parents need a wake-up call about how much work goes into educating a kid, and that they need bear more responsibility. I'd love it if public schools could charge sliding-scale tuition (and that $$$ would have to be shifted around, because schools serving poor neighborhoods would have very little coming in). There also needs to be a cultural shift in how kids are raised...kids are coming in more and more underparented every year and less and less able to deal with life.
Unfortunately, a lot of the problems with parents come down to people breeding who shouldn't. The end.
TL;DR: Good old days weren't always good (with apologies to Billy Joel). Expectations of what schools are expected to do has kept expanding, but budgets have not kept up.