Vercel's moat is DX in hosting, not NextJS. Consider, people who switch to TanStack Start still need a place to host and many would continue to choose Vercel.

Same principle applies, hosting in Railway has slightly worse UX, but with LLM's you don't need to write a single docker line anymore, so deploying on railway is way way less cumbersome than before, and you gain more control and less costs.

This moat is rapidly disappearing though. Cloudflare is catching up, most apps (including TanStack Start) can be one-click deployed without configuration now.