I forgot to add the last straw for me was the removal of GIMP's 'Fade' feature. I'm aware of the alterative but it's not as convenient.
User ergonomics in software is extremely important and its removal is a big anti-feature. At the time GIMP's developers didn't offer an apology, they just said that's the way it's going to be on 'technical grounds'.
What did you drop it in favor of?
Paint.NET, Inkscape, Krita, CinePaint, ImageMagick (command line - yes, it can be very useful at times), and various others when certain needs dictate.
Also, Photoshop CS3 which is my last paid version (moreover, I can still reinstall it as Adobe temporarily released a general version with an unlocked key when it abolished the CS3 licensing server some years ago).
I even use IrfanView viewer as it has a nice batch converter (although it's no good for 48-bit work).
Frankly, there's no shortage of image editors even after eliminating GIMP and Photoshop.
I can only conclude the reason that these inherent problems with GIMP have remained uncorrected for so long is that its developers couldn't give a damn whether we use it or not.
It seems only a play toy for its cliquey developers and the only reason it's available at all is that we gullible users act as occasional bug detectors.
Sure, open software has resoure problems hence expected delays but too much water has flowed under the bridge for that now to be a viable excuse.