Cloud providers have put a lot of time and effort into making you believe every web app needs 99.9999% availability. Making you pay for auto scaled compute, load balancers, shared storage, HA databases, etc, etc.
All of this just adds so much extra complexity. If I'm running Amazon.com then sure, but your average app is just fine on a single VM.
Marketing has such a gigantic influence in our field. It is absolutely insane. It feels unavoidable, since IT is (was?) constantly filled with new blood that picks up where people left off.
And funnily recently many of the Big Serious Cloud Websites are shitting the bed of availability aggressively.