After acquisition - we were handed down the order to migrate to AWS.
This was after (in the mess of the merger) the colo contracts were basically ignored and not renewed. Once someone within the company realized the issue, it was the 11th hour.
After many, many attempts to discuss our (Operations team) concerns, we abandoned our protests. It was clear the new CTO wouldn't cave and sign the contract.
Some superficial testing was conducted and the order came down to move...NOW.
We began moving hundreds (maybe thousands) of very resource hungry DB servers first (there was no way to use something like RDS without major app/config changes).
Once the AWS bill came in, the CFO blew their lid and within 90 days we were migrating BACK to our DCs (and the millions of dollars of hardware we left idling).
Our GIS clients run WS as a Deskstop OS with ESRIs ArcGIS Pro. Incredibly common.
And once you have that - add in Active directory, DFS and random Windows Servers for running archaic proprietary licensing services.