But I think a lot of it is also about knowledge and documentation. If I want to copy FAANG or another startup, and set up an infinitely scalable queue-based architecture, I can find dozens of high quality guides, tutorials, white papers etc, showing me exactly how to do it. Yes maintenance is higher, but I can get set up with redis, SQS, any of the 'scalable' solutions within a few hours of copy-pasting commands and code and configuration from a reputable source.
If I want to use NOTIFY in postgres? I googled "SQLALchemy notify listen postgres" and I find a few unanswered stackoverflow questions and a github gist that has some code but no context.
I would honestly love to use this approach for a side project, but I don't have 2-3 days to figure it out on my own. The direct choice for me might seem to be
* simple, but not scalable (ie just use postgres)
* complex, but scalable (ie redis, sqs, whatever)
and then it's a tradeoff, and the argument goes that I am blinded by cool tech and FAANG and I'm choosing complex but scalable, even though I don't need scalable.
But taking into account guides and other resources, the choice for me is actually
* complex and not scalable (this, because I don't know how to implement it and I can't predict what pitfalls I might face if I try)
* simple and scalable (what everyone actually does)
and that makes the engineer's choice to follow faang look a lot more reasonable.
Also: you may think that you may one day want to be hired by a FAANG.