Bobby Lee says the MadTV cast were “looked down on” in Hollywood

I believe this. Lorne and SNL are very big power players in Tinseltown. MadTV was direct competition, likely owned by the wrong politics. I bet there was a lot of backdoor blacklisting going on.

MAD TV demonstrated comedy. SNL hasn't understood the concept for decades.

Yeah. Sounds about right. I always noticed how much easier it seemed to be for even middling talent on SNL to get other opportunities starring in major film & television projects. It was apparent to see that even the top MAD TV stars in their prime weren't getting these opportunities.

Phil Lamar went on to have a steady voice acting career. Alex Borstein got lucky with Family Guy & finally a supporting role on 'The Marvelous Mrs. Maisel' Aries Spears went back to his stand up roots. Debra Wilson has had a steady voice acting career as well. The biggest thing I'm aware of that Will Sasso has done is that Three Stooges movie that apparently bombed. Ike Barenholtz has actually had a surprising number of small supporting roles in major films.

I literally have no idea what Michael McDonald has done outside of Mad TV until I heard he turned up as one of Michael Myers victim in the last Holloween movie. Ironic sidenote: Michael McDonald has been killed on screen by two different people named Michael Myers. Once in Austin Powers & again in Halloween