Moving to a subscription model is largely a symptom of that coasting. They couldn’t consistently come up with compelling reasons to upgrade to new versions of Creative Suite, with users being perfectly happy to run what they had for as many years as possible.
They were always going to hit a ceiling on interesting features to implement, but they could’ve sold new CS versions on improvements in stability, performance, responsiveness, and efficiency (things that users care quite a lot about), but that kind of engineering work doesn’t work well with the cheaper model of continuously adding to the ball of mud.
There is another element at play: modern software product management. I think revenues at the main driver, but behind that is the modern PM philosophy of hypothesis-driven development. In my experience, the average outcome is incrementalism in the extreme.
PMs break every feature down as an experiment to try and measure the value. It often misses consideration of the whole product. Everyone is scared of taking a big bet because it's harder to measure and too risky because all of these small bets are seemingly safer.
What I'd argue for is better product leadership that recognizes these new modes of development are just a tool. However, many product teams have become cults of experimentation and I expect this is the case at Adobe. It pays off as long as people are renewing, but the product suffers.
With the software professional industries really care about (like InDesign) instead of messing with it they instead took approach of never changing it to not upset anyone. And instead of paying 1200usd one time people accepted paying 60usd month rent. I know places that still use CS6 and InDesign CS6 vs the current one is almost indistinguishable software. There are maybe 5 minor new features that anybody cares about in the current one. It's insane that in those 10 years somebody payed adobe over 7k. Users should revolt.
They were always going to hit a ceiling on interesting features to implement, but they could’ve sold new CS versions on improvements in stability, performance, responsiveness, and efficiency (things that users care quite a lot about), but that kind of engineering work doesn’t work well with the cheaper model of continuously adding to the ball of mud.