Rick Perry has frequently proposed doing so. But the consequences are obvious:

Block-granting may be attractive to some federal policymakers as a way to cut federal Medicaid costs.  But states would be left holding the bag when federal funding proved inadequate; they’d be the ones who would have to increase their own funding or make the tough decisions about which people to drop from coverage or which medical services to curtail.

Shifting costs around is not controlling costs. Not that hard to understand. But Perry, it appears, is truly stupid. His college transcript does not exactly refudiate this.