Yes and no.
There was a similar collapse at the other end of the scale. If my memory is correct, Alaska is the only major US airline still flying turboprops, which are actually more efficient than jet engines at the size category. And the ones they do fly are big.
The US industry has been moving to wipe out all aircraft below 76 seats, which in turn means the elimination of direct flights to smaller markets. Instead, those folks are being asked to drive to a larger regional airport.
American Eagle, for example, had a fleet of 100 Saab 340 planes, which held ~35 passengers. No major airline brand is flying that size anymore.
And before someone rushes in and says Cape Air...
Cape Air is not a major airline.