more users means, they should do much better than the ones with less users (assuming each user is worth the same/requires same infra).

at the worst case, a bigger org could just copy paste a smaller orgs system a couple times to get the exact same uptime, with same budget per user*. The benefit of bigger orgs is, that they can consolidate these separate system a big system that is more stable AND costs less. If this wasn't true, we wouldn't have big orgs in the first place**.

* yes, it is NOT the same budget for the users. You can't JUST copy paste the system, you'd also need to think how you split it up. I know there are a million little things to nitpick here, but this can all be solved somewhat easily, and they wont change the overall argument.

** regulatory capture, lobbying, corruption and creating a monopoly could also be consider aspects of "consolidating into a bigger system". This doesn't mean why MS shouldn't be able to be better, it just explains why they aren't better.