It seems like B2B consumers pay a lot of money to get rid of that pesky "as is, without warranty" clause. It seems like almost every business that is paying for something they could do in-house for free, is basically paying for it because of this. They don't want to outsource the actual labour, per se - they want to outsource the blame when it goes wrong, even if the actual uptime percentage is identical or worse. Centralization is an advantage here - if we say "we're down because five other websites are down, sorry" it looks worse than "we're down because half the internet is down, sorry"

More generally, they want to have a contract for services with someone. That's what's really meant by "support". Not merely being able to call tech support, but having people backing their services. The really big places have their own engineers, and the really small places can't afford it, but the middle-sized places would rather pay you to support them as needed, than hire someone on their side dedicated to managing your product.

The illusion of support can also sell just as well as actual support. Just see Oracle vs Postgres...