It's usually not a money thing, it's that the customers are usually unable to maintain the service internally resulting in extremely outdated, insecure, and poor performing versions of your product everywhere generating a lot of support issues and bad vibes around your product.
I think that's fair but on the flip side there's ways of handling on prem much better than Atlassian does. GitHub would be a good example of that. It's throwing the baby out with the bathwater.
