That is a new NBER Working Paper by Angrist, Autor, Hudson, and Pallais. Here is the sentence of interest for the recent community college initiative:
Awards offered to prospective community college students had little effect on college enrollment or the type of college attended.
Do note that some other kinds of awards appeared to be more effective, so this is not an anti-subsidy result per se. And here is a new Bulman and Hoxby paper on federal tax credits and the demand for higher education (not just community colleges):
We assess several explanations why the credits appear to have negligible causal effects.