That's the point, the "rock" stars aren't making any money in the industry like other pop acts anymore - they're mostly doing their own thing on Patreon and streaming on Twitch.
If they're recording music, they can certainly still use Logic to do it, and Apple wants to give them reasons to keep doing so. It's hard not to notice that Apple has been courting YouTubers really heavily over the last few years.
Look at someone like Billie Eilish and her Apple Music-exlusive content. Obviously not literally "rock", but becoming a global star is still very much a thing.
In this Rolling Stone video she and her brother walk through how they made "Bad Guy," I don't know audio software enough to know if this is Logic but I'm sure a Logic users would recognize it in some of the shots if so:
Lennon, Tesla, and JFK were deeply flawed human beings living in a different time, with far less media coverage than today. I suspect your view of the past may be unfairly rosy due to the effects of time.
Billie Eilish is simply the current incarnation of the "breathy misfit 'poet' girl singer" that comes around over and over and over and over. And then disappears.
I hope she makes an enormous amount of money while she's popular and has a smart enough brain to bank it for when she is not.
Not really in 2020.