It seems somewhat unlikely for a number of reasons. The article was quite long, so I didn't read it all, but a key takeaway seemed to be "Gatsby only uses the s

It seems somewhat unlikely for a number of reasons. The article was quite long, so I didn't read it all, but a key takeaway seemed to be "Gatsby only uses the server-side rendering APIs when building for production". SvelteKit does SSR rendering in development as well, so you wouldn't have the issue of dev and production being different in that way. Also, Svelte's hydration works a bit differently than React's.