Absolutely, and Microsoft knows this. You could even upgrade a pirated version of Windows to a legit copy when they did the upgrade drive for 7 I believe it was. Did it myself. And they completely turn a blind eye to OEM key reselling, which is why you can get legit windows keys for less than $10 these days.
They've also never done anything substantial against pirates, all they do is pester about buying a key and warn about the risks. The "worst" they do is stop you from using windows update which some see as a feature. When they could just completely lock you out and/or report you to the police.
The money is in server for Microsoft, but they're losing that battle slowly but surely since they can't make windows actually work properly in a container setting. I have customers that love Microsoft but despite their best efforts at making containerized windows workloads work it just sucks major ass. And virtually everybody is coming around to realize just how insane of a paradigm shift containers are.
And losing that battle is why 12 will likely move to subscription. And I'm willing to bet money that, in 10 years time, will be considered the starting point for Microsofts dramatic loss of market share in the home PC market. From 90% or so now down to like 50 ish %. But maybe some smart guys at Microsoft will nip that in the bud.