I didn't plan to upgrade my Pixel 7 Pro anytime soon (it should last me until the Pixel 10 perhaps). But a Pixel with a Desktop Mode would be really tempting.
When I thought about buying the Pixel Tablet it became clear to me that I don't want more devices, I want versatile devices. Maybe folding phones will fill that gap for me once they mature enough (and become less expensive) but for now hooking up a phone to a monitor seems the better option, at least for me.
AFAIK the reason that it hasn't been supported so far is because of the additional fees and or hardware necessary for hdcp protection of the signal. Either way Google will be eating this new cost or raising the prices to compensate.