What are some tv stars that failed to jumpstart a film career when they transitioned from tv? Why was that?

I guess some infamous examples would be Shelley Long from Cheers (though she had some successful films I believe) or David Caruso from NYPD Blue.

I was watching 90210 recently and thought of Luke Perry. He did Buffy the Vampire Slayer and 8 Seconds during his summer hiatuses from the show but left during season 6 for a film career that never materialized. Movies like American Strays and Normal Life failed so he returned to tv a few years after.

I'd wager that he was typecast as a teen drama star or maybe he simply waited too long (leaving in 1995) versus when he was most popular (1991/1992/1993). Or maybe just he stood no chance of getting good roles against the likes of bigger A-list movie stars.