The issue that undermines you’re (mostly correct) observations on slowing moving enterprise, is that they’ll often adopt technology before knowing if it will even work the way they want it to. So when it comes time to implement, you’ll find things that don’t work as described, often accompanied by some years old issue on their tracker which basically say “we might get around to that some time”.
“Enterprise grade” proprietary software is usually terrible anyway, so still prefer open source for the reason that I’m able to write my own patches for it (which I often do). But I find the open source attitude toward fixing issues, in software that your customers are actually paying a lot of money for, incredibly frustrating. There’s a particular maintainer on a project that I use a lot at work, and anytime I see his avatar on the forum while trying to debug an issue, I instantaneously know that my whole day is about to be ruined by some of the least helpful advice you could possibly imagine.
Large corporations (which the $10k/mo user probably is) on the other hand calculate updates in months or even years.
My company also has a very large customer that asks us to implement something "whenever possible" and if we need 2 years they are just happy we did it. Why? Because they have a long update cycle. It's not really important if it's in the next release because they might not even install that but wait for the release after that.