However a concrete example is the "pulling up the ladder behind you" effect of regulatory capture.

There are more people who want to become doctors than our country allows to become doctors.

Our current state of affairs regarding compulsory medical residency programs is a result of years of increasing the barriers to entry (for good or bad reasons, doesn't really matter). Now it's up to Congress to pass Medicare reform laws to update their funding for the residency programs, but that has just not happened (one of the major I-told-you-sos when dealing with government intervention).

It's probably not the case that we want to completely deregulate, however a major consequence of almost any regulatory intervention that operates on the basis of increasing credentialism is that we will end up with some % less than ideal supply.