In 1995 it cost us the equivalent of $2k up front to buy Photoshop. I think there was actually a small discount but it was a hecking big payout. You'd get to keep that version forever, but what if you only needed it for a month? What happened when just a year later Photoshop 4 came out? Tough.
I get that software subscriptions suck, but it's the compromise that makes it both affordable to you in your life, and affordable to Adobe.