Whoever we tax, where do that get their money from? Even if the government pays, where do their funds come from? Taxes that would have to be raised, so technically the people are paying for their own college tuition.
"Wall street and rich people" May have people who cannot afford high taxes living near them. Just because they are "rich" doesn't mean that they should pay for their rich neighbor's college tuition. The government will make the country contribute to the tax, not just "Wall street and rich people." College is normally extremely expensive and the government and "rich people" cannot pay for some strangers tuition.
One of the main problems in the United states is that the taxes are to high. If college was "free" then the taxes would be raised even higher. This would lead to protests and angry citizens. Nobody wants to pay for a complete stranger's college tuition.
Overall, even if collages were "free", someone has to pay the teachers and faculty. The people who would pay is anyone who is taxed. High taxes is already an issue, people don't want them to be any higher. Therefore, students should have to pay for their own college education to teach them responsibility and independence.