A lot of us work at big companies with lots of users and demand and aren't just making POCs, but every time we bring up scaling or maintenance or monitoring we are told not to worry about that yet.
This whole Tell HN is about personal projects where costs matter, the startup tangent here is just a jab at people underestimating the raw processing power of modern hardware.
Big corps can do what big corps do with their big corp money. 200 user startups don't necessarily have hate kind of money but pretend they will be big corp very soon and thus need to spend big corp money.
But then there will probably needs to be a devops team and careful planning how to architect infrastructure anyway.
Also in such cases cloud pricing becomes prohibitively expensive unless you get a special deal.
Scalability should be the last thing in mind if your product sucks.