My take is that Elon is suing OpenAI because he left OpenAI before they opened a commercial venture, which means he doesn't benefit from the companies current valuation, so he's using the courts to try to strong arm the foundation into giving him some shares, basically using the courts for harassment purposes.
I'm hoping for both to get fucked, and if this takes this whole "AI" hype away with them, so much the better.
In my dream world we'd nuke M$ from orbit and splinter it into a trillion tiny little pieces... A man can dream
According to the Isaacson book, Sam offered Elon equity in the for-profit arm of OpenAI but he declined. He is clearly motivated by the original mission, i.e. the Open part.