Krita is fine for painting but isn't a full replacement for Photoshop. Inkscape does vectors, which is something else different entirely.
If GIMP prioritized matching Photoshop's UX to make it easy to switch over (shortcuts, UI similarity, etc.), it'd be much more successful at converting Photoshop users. Serious Photoshop users at this point have spent more than a decade (!) committing these things to muscle memory.
GIMP hasn't made replicating Photoshop's UX a priority, so it isn't a replacement for someone more comfortable using the industry standard tool.
If I used Vim for a decade, then you said,
"Notepad++ also edits text, why don't you switch over?" Well, I'm not as productive in Notepad++, and I don't think I'll ever be. Same for GIMP.
Although I agree, one key difference from this case and your analogy between Vim and Notepad++ is you don't save a few hundred/thousand dollars switching from Vim to Notepad++.
That's an extra factor that, at least for me, made it worth switching and investing some hours into adjusting for hotkeys/shortcuts/etc. To be fair to your point though, I don't have a decade of full-time work invested into Photoshop so perhaps my muscle memory was more malleable.
Not only the money is the issue, also your livelihood if you live in a country where the US can decide from one day to the next to sanction it for what ever reason, and cutting your access to any cloud service.
They should have an 'industry standard' keymap option on first start like Blender. But it's not nearly as weird as Blender was: there's no right click select, and eg. the cloning tool is basically the same thing as Photoshop's, though the large variety of select tools is a bit intimidating.
GIMP is ...not very good. Fixing the UI and UX wouldn't change that. Compared to GIMP, as a project, Krita is in another dimension.
If any software is going to become a successful FLOSS Photoshop replacement it's either Krita (if they decide to go that route instead of just painting) in a few years, a new open source project with an impressive MVP (like Olive the video editor, to Adobe Premiere), or some kind of miracle like one of their commercial competitors deciding to open source it.
Yeah, they seem to be off to a fairly slow start. This isn't the first Gimp fork to try to work on UX - but biting off a huge old codebase isn't easy and previous efforts have all been overwhelmed or overtaken by upstream and fizzled out, afaik.
i'm not convinced the issue is GIMP not matching Photoshop so much as it having awkward UX that's hard to adapt to. Also, Photoshop 1.0 was released in 1990 (!)
If GIMP prioritized matching Photoshop's UX to make it easy to switch over (shortcuts, UI similarity, etc.), it'd be much more successful at converting Photoshop users. Serious Photoshop users at this point have spent more than a decade (!) committing these things to muscle memory.
GIMP hasn't made replicating Photoshop's UX a priority, so it isn't a replacement for someone more comfortable using the industry standard tool.
If I used Vim for a decade, then you said, "Notepad++ also edits text, why don't you switch over?" Well, I'm not as productive in Notepad++, and I don't think I'll ever be. Same for GIMP.