Maybe in recent years, but back in the '70s and '80s no one spent more time on the screen than Dr. Gene Scott.
R.I.P. He wanted to keep doing “Millionaire” but they went another route doing a 30 minute version. So he did a couple of times a different game show on CBS. I think it was Celebrity Password and America’s Got Talent a few years later replaced by Springer. He also retired from his morning show in 2011 but then was on a sports show on FS1 that ended after he quit the program. Guy had the most hours on American Television.
The prime time show as ended - though they would still return occasionally with specials that he would host.