Svelte creator and Vercel employee here. Vercel does indeed invest heavily in Svelte and SvelteKit, not least by employing me and Simon Holthausen (and potentially others in future), but there's no danger of lock-in — we're just two members of a much larger core team. Governance-wise, it's an independent project, and we'd be thrilled if other companies also chose to employ core team members! You can see pull requests like https://github.com/sveltejs/kit/pull/8740 as an example of how we approach the relationship between SvelteKit and Vercel — we're adding a new feature and Vercel will be the first adapter that gets to take advantage of it, but we're careful to design the feature in a platform-agnostic way (we even @'d a Netlify engineer to make sure that they're aware of the work in case they also want to take advantage of it).

Anyway, I'm sure this will be said elsewhere in the thread but it bears repeating — the Next team similarly works hard to make sure that your Next apps can be self-hosted and run on other platforms.