Ah we never saw that one coming. What really bugs me is why people keep defending these companies: this is straight up abusive, and we - all of us - should not accept these tricks. Getting you an MS account is one small step away from charging you monthly for the privilege of using the computer that you've already paid for.
That's already a thing - unfortunately - the only way to get Windows 10/11 Enterprise is via a subscription, though they're careful not to word it as such. There are three ways to get it: (1) you can either buy it through the volume license channel which requires an active software assurance agreement to continue legally using the latest build [though you can legally reinstall the LTSC branch for as long as that's supported]; (2) you can also get a subscription for Windows E3/E5 for ~$84/yr from M365. Which, if you price out the volume license with SA it works out to about the same yearly cost as M365, funny how that works. (3) Finally if you're an MSDN subscriber you get some number of non-prod keys for Windows Enterprise.
So I agree with you 100%, the writing is on the wall, Windows will absolutely become a subscription service in the next few years. (Thankfully I've been distancing myself from Windows in anticipation of this event. As soon as it was described as "Windows as a Service" in marketing material I immediately installed Linux on my main workstation, and stuffed Windows inside a VM w/ PCIe passthrough for the GPU.)
My guess is they'll bundle Home into M365 family, Pro will remain available to consumers in the OEM channel, but will primarily be meant an upgrade available for M365 business subscribers, and Enterprise will remain mostly unchanged as the volume license option.