Color me unsurprised. The Win10 practice has been to drop support for a previous feature update not more than 2 years after a new one is released - usually 12-18 months. So if "Windows 11" appears as 21H2, the end of 2023 is what would be expected for EOL on anything older. We all know that MS is a little more lenient than that, especially for Enterprise and Server SKUs (my work laptop was running 1709 until late last year, when it got 1909, and last week got 20H2).
The question for me is whether MS is calling this a new OS because they want to exercise that clause in the TOS that lets them cut off support for older hardware. IOW end backward compatibility to a major extent. That would be, in essence, pulling an Apple - buy a new computer or go away. I only recently rebuilt (with 10th gen Intel) a 15-yr-old rig that was running Win10 (fully updated) just fine. Still have a 10ish-yr-old laptop ditto, and a 4-yr-old tablet/2-in-1 ditto. I kind of figure "11" won't have a 32-bit version any more which kills off the tablet. How about the old laptop (1st gen i5) with 4G RAM?
And yes: what's it going to cost? Will MS return to paid upgrades? In that past, that was manageable, because if you didn't want to be on the bleeding edge you still got security support of the old version for 5 or more years. This seems to be a change to that policy, as well.