I run a business that is a long long way from a stock exchange or a payment processor. And while a few minutes of downtime is fine 30 minutes or a few hours at the wrong time will really make my customers quite sad. I've been woken in the small hours with technical problems maybe a couple of times over the last 8 years of running it and am quite willing to pay more for my hosting to avoid that happening again.

Not for Heroku, they're absolute garbage these days, but definitely for a better run PaaS.

Plenty of situations where running it yourself makes sense of course. If you have the people and the skills available (and the cost tradeoffs make sense) or if downtime really doesn't matter much at all to you then go ahead and consider things like this (or possibly simpler self hosting options, it depdns).But no, "you gotta run kubernettes yourself unless you're a stock exchange" is not a sensible position.