What AWS gives you is the ability to spin up dozens if not thousands of hosts in a single click.

If you run your own hardware, getting stuff shipped to a datacenter and installed is 2 to 4 weeks (and potentially much longer based on how efficient your pipeline is)

If you own your own hardware, but you can provision a leased dedicated server from many different providers in an hour or three, and still pay far less than for comparable hardware from AWS.

Which is an awesome capability, if you need it.

I suspect that if you broke projects on AWS down by the numbers, the vast majority don't needed it.

There are other benefits to using AWS (and drawbacks) bit "easy scaling" isn't just premature optimisation because if you build something to do something it's never going to do that's not optimisation it's simply waste.

But on Hetzner, you can usually get a dedicated server installed and ready tomorrow.