I think you're overstating it. Why do people care so much about scalability issues, anyway? Given that (a) a stateless server plus an SQLite instance is much, much easier to set up than the proprietary, poorly documented mess that is Lambda, (b) that server can easily be horizontally scaled, and the SQLite instance can be swapped out with any other SQL database with some effort, and (c) a single server with SQLite will easily handle up to 100K connections, it doesn't seem like scaling was ever an issue for most websites.
I don't think you've used the tools that can work with lambda or had to actually scale something in production, based on your response...
It's all a lot harder than you make it out to be, but at least with lambda (and something like Zappa) you don't have to figure anything out beyond how you get your first environment up. There's just no second step, and that's huge.
Using a scripting language like Python or Node it literally is adding one function that takes in a JSON event and a context object as your entry point.