In many ways it is a luxury to be able to use said abstractions and be able to open a ticket with someone else. Of course, a single-person startup could use the same tech, but it seriously impacts their costs and they don't have time to deal with the sprawl of abstractions.
Whereas when you are a one-man business, all you have is (free) time and prefer to spend as little money as possible while your business is not profitable. This means: walk away from dedicated databases, managed servers, huge aws bills, etc. You do everything "the old" way: rent a server (bare metal or cloud) and maintain it yourself.
This pattern plays out with many indie app developers as well, both now with iOS apps, and back in the day with Delphi shareware. The cost of taking a dependency on a 3rd party library turns out to be much higher for the solo developer than larger orgs. That's not to say they don't make bets, but they don't build the way that someone at a larger org would do because they have to maintain a higher degree of direct control.
Marco Arment (https://marco.org/) has elaborated a lot on this topic. You can also get a feel for the limits on the upper bounds of his developer experience. Many on HN are not willing to work at a low-level with such boring and dull technologies.