I think this is true of a lot of software, really. Very few people need more out of their office suite than what’s available in MS Office 2000 for example, which is somewhat validated in the sheer popularity of GSuite (with e.g. Docs being little more than WordPad/TextEdit with collaboration bolted on).
In general I also think that fixed-feature projects are a woefully underexplored space in the FOSS scene, which is a shame because they’re structurally more sustainable than projects that endlessly add new features.
The main reason I never upgraded was that it was FAST, and until Adobe started rolling out AI features around 2020 there were almost no notable additions made to Photoshop other than new versions seemingly getting slower and arguably uglier. To this day I'll still occasionally boot up the old Photoshop 7 if I don't need to use content-aware fill, and I'll marvel at how zippy it feels.
And yeah, 7 was quite efficient and zippy, basically just 6 with a few new features and compatibility with newer OSes (first version to run natively on OS X for example). Ran it on a 400Mhz G3 without issue, which would be futile to even attempt with modern versions.