Knowing that they will stop working in a couple of years also devalues them. Seriously, a patch to remove DRM for those who are unable or unwilling to upgrade.
A company that can be trusted to deliver that patch will have a more valuable product because customers know they will not lose access to it.
Yeah that's a fair point in the other direction. But I guess to some extent when you have a de-facto monopoly on a market it doesn't matter what you do to your customers, most of them will buy your new subscription model anyway out of necessity.
That's probably why there are suddenly a lot of Photoshop competitors. A monopolist abusing their market creates an incentive for competition. Of course some monopolised markets can be very hard to impossible to enter for competitors, but that's apparently not the case here.
A company that can be trusted to deliver that patch will have a more valuable product because customers know they will not lose access to it.