The need to adapt videogames into movies is driven by the belief that videogames are not "legitimate". You have to process a videogame into a format the average normie can understand.

This is also why videogames that are the most like movies often get praised the most for being "art" (see: The Last of Us). They've taken the videogame, cut it up into little pieces for you and practically chew it for you to ensure it's the easiest thing to digest.

I suspect after The Last of Us's show success, which itself got heaps of praise for being such a good adaptation when it is arguably one of the easiest things to do, more studios have been prowling around searching for videogame IPs to adapt. Especially with the superhero genre cooling off. Try to make videogame adaptations the hit new thing instead of comic books. On the animation side of things, the Super Mario Bros. movie has definitely got people to line up more animated videogame movies.