If you host your non-nextjs SPA on Cloudflare and they do something you hate.. you move
Vercel has every incentive to lock everyone in as hard as possible and raise prices all they can. Not something I'd want to tie my business to
It will be evenn worse when they see they need one, two, three more engineers to deal with the Next.js mess they created.
The app router kinda sucks so we're staying with /pages. No complaints thus far with a team of 6 engineers.