Realistically this doesn't change much since it's extremely unlikely a foster kid wouldn't qualify for a full ride prior to this.
The only people who really get screwed are middle class families who make too much to qualify for aid, but can't really afford to pay for school.
Rent/living cost is another matter, but tuition can be still be reasonable if you state in state and don’t attend expense universities.
But I totally agree - there is a lower/lower middle class of people that attending college is vet challenging and free tuition for all at some schools would be massively beneficial for them and society.