Never saw The Black Stallion. Yes, he got work in a lot tv episodes, but except for a movie here and there, his star until Sugar Babies was mostly declining. Didn’t dislike him...just never much of a fan.
No, he had an amazing decades long career. Every great star has down periods but Mickey worked consistently through the 50s and 60s - check out IMDB. I’ll never forget his brilliance in Sugar Babies - an honor to see he and Ann Miller live. As my brother just reminded me, Laurence Olivier called him a great actor. Not too shabby.