There isn't just one way, but from what I can tell AWS works great for the really small and the really big, and is a massive waste of money for the in-between. They have run an amazingly effective marketing campaign to make everyone feel like they are missing out if they aren't using it.

The learning curve for working with AWS is similar to the learning curve of working on bare metal. It honestly does not take a specialist to use MySQL, Postgres, etc. They are really quite easy to make a HA turnkey solution. It's as easy as learning how to effectively use an amazon service. We aren't talking about the days where you had to shard out which was a big pain in the ass, because machines are cheap now with 128 physical cores, 1tb of memory, massive fast storage, etc. You can run the nastiest largest database on a single machine and achieve a pretty large scale doing it.

One of these paths costs about $2500 a month with server purchase amortization, and on the other about $20,000 per month. Either way I need someone to manage it (unless you are talking heroku level of turn-key, then up that $20k a month to $50k a month).