Inkscape is similar - everything is a little harder to do - and there's some basic things that don't seem to be in the application at all. Does Inkscape support multiple artboards yet? What about exporting multiple resolutions without duplicating the assets? The symbol support also was very lackluster when I used it last.
Krita lags horribly every time I've tried to use it.
I like the notion that there are open source replacements for these systems.. and I'd love to drop my $50+ per month subscription - but the alternatives aren't yet equivalents.
Basically, yes, it hurts, but maybe try using it more? It's certainly better than nothing, which is what we may have if, I dunno, Adobe collapses or something crazy and all our Photoshop licenses suddenly stop working.
I actually feel the exact opposite - it's easier to use than Photoshop - but that's probably because I used GIMP before I ever had access to Photoshop.
100% agree about Inkscape, though.
Krita: Constant random crashes, like seemingly every complex Qt application.
Inkscape: I grew up on CorelDraw so maybe I just have the wrong set of expectations, but the UX is full of papercuts and inexplicable choices. For just one example that annoyed me recently, it seemed completely impossible to get snapping to grids and guidelines to behave; some objects would just refuse to snap to certain targets (different set for each object), and generally the snapping seemed to be based on arbitrary "basepoints" (only one per object; can you change those?) rather than bounding boxes.
(Blender, brought up elsewhere: actually quite good (modulo maybe the confusing refcounting/resource management), once you get on top of the learning curve. I hope 2.8, which I haven't tried yet, hasn't changed this.)
This is what macOS does, and does it well. Aqua/Quartz (is it still called that?) doesn't support (or at least doesn't encourage) MDI either, but unlike Windows it's app-centric instead of document-centric, which can annoy some Windows users when ALL of an app's windows come to front when they click on its icon in the dock.
Also, when you're making artwork on a deadline, fooling with virtual machines and things like that just doesn't make sense. There are just too many moving parts. Having to deal with layers of technology is a serious impediment to letting your creativity flow.
I first installed Linux off of floppies in the mid-90s on a hand-me-down 486— my distaste for that workflow isn't born from lack of experience or technical knowlege— it's born from the knowledge of the very real consequences of having an overly complicated toolchain when doing time-sensitive work.
That said, I only use it a couple times a month. If I had to run it professionally, I'm not sure I'd be down.