Next.js is extremely limited compared to Rails, so you're still not comparing apples to apples. Add to next.js a librarydatabase access, background jobs, csrf and related security stuff, migrations, server side caching of data, *validation*, email sending, email receiving, testing, and I could spend an entire day listing things Rails gives you that Next.js won't give you. Web development is not just rendering html, unless you're building just landing pages, there's a lot more going on.