Let's say Mama Cass (The Mamas and the Papas) takes better care of herself and doesn't die at just 32?
What would she achieve in the 80s and 90s?
The Mamas and the Papas may have a few reunion gigs and maybe make a special single or two together. But mainly I could see Mama Cass Elliot, carrying on her solo career, with maybe jumping into acting, similar to Barbara Streisand, by gaining a small (cameo) role, in 1975, with "The Rocky Horror Picture Show" before hitting the screen in 1978, Grease.
She would later become famous for modelling for fashion and clothing stores who wanted to appeal to the larger ladies. We might also see, big women, being more socially accepted as attractive.