I don't think that's ever saved money.
> because if they had that experience, they would have never written this article.
That's not true.
I spent about a year as a consultant in the AWS space, visited about ~15 clients of varying sizes.
More often than not there's a single pg aurora instance responsible for 50%+ of the bill. Even worse are the serverless aurora offenders.
All the indexes and guarantees of PG don't come cheaply and dynamodb pricing is not cheap but comparatively reasonable. It really is a good product if you know how to use it.
No. If you're struggling to build software against a DB and then abstract parts to use Redis or ES or whatever in the future, that's kinda a skill issue you or your team have with building poor software to begin with. Nothing to do with using a DB for multiple things like a Queue/Search etc.
It’s the business modeling skill that most developers lack, so they skip it and believe an ERD will magically cover all invariants.