That's plainly false. $50k will cover nearly all state schools, in-state.
The vast majority of all state schools are less than $12,500 per year for tuition + fees in-state. The exceptions tend to be among the top state schools, like UC Berkely (~$60k) and Virginia (~$70k). The $50k equivalent would still go a very long ways for those.
George Institute of Technology is $12,500 per year in-state for tuition + fees.
University of Florida is $6k per year.
Purdue is $10k per year.
The University of Houston is ~$8k per year. Texas A&M is $10k per year.
A bunch of the Cal schools are around $7k per year.
The same goes for the city schools in NY (CUNY), those are mostly around or under $7k per year.
UNC Chapel Hill is $9k per year.
UCLA is $13k per year.
The University of Michigan is $15k per year.
University of Texas at El Paso & San Antonio are around $7k per year. Texas at Austin is $10k per year. Texas Tech is $8k per year.
And this is the cost for some of the best state schools. Everybody else is between cheaper and dramatically cheaper. The primary requirement is that you have to go to an in-state school. I'd bet that the in-state median for state schools across the US is a lot closer to $6k per year, rather than $12,000.
$50k will not cover many state schools. Especially if prices continue to climb.