Not only that. When your self-host goes down your customers complain that you are down. When AWS goes down your customers complain that internet is down

AWS doesn't have to pay people (LOTS OF PEOPLE) to keep things running over the weekends?

And they aren't...just passing those costs on to their customers?

They are of course, but it's amortized over many users. If you're a small company, it's hard to hire one-tenth of an SRE.

Not every business needs that kind of uptime.

How often is GitHub down? We are all just fine without it for a while.