In the run up to the expansion of Medicaid by states, some of the fecal matter flung at the wall by anti-Obama types was that, if Medicaid expansion took hold, the system would be overwhelmed and collapse under the burden of all those new people actually getting access to affordable health care. In Michigan, Gov. Snyder, who eventually DID sign Medicaid expansion into law, actually used that as an excuse for considering vetoing the bill:

The key issue on the Medicaid expansion that I want to do some research on, among others, is do we have enough capacity to put essentially 400,000 more people into a medical home model with a primary care environment, as opposed to having them simply go to an ER?

In other words, we can't have nice things, at least not in Michigan.
However, a new report out of the University of Michigan shows that not only was this fear unfounded, for Medicaid patients, the availability of appointments is actually BETTER now than before the expansion. For those with private insurance, it's essentially the same.