ZD,
Yeshivas in the past were also at least as dependent on contributions. Many more parents could not pay tuition.
As far as well of frum Jews, Boruch hashem there are number of chareidi billionaires who are very philanthropic and support yeshivas, kollelim and other causes. In amounts that you are probably unwilling to fathom. Your unawareness is only an indication of your lack of knowledge and nothing to do with reality.