I agree. As a photographer, I use Lightroom and Photoshop for most of my post-processing needs. Lightroom, when it hit, barely felt like an Adobe application (it's great), but Photoshop has always been a nightmare of crashes. CS5 on OS X is especially bad.
As an experiment, I tried to use (only) Lightroom and Pixelmator[1], which is the closest "indie" alternative to Photoshop I could find/had experience with. Note that GIMP was out as 2.8 wasn't released by then, and older versions were horribly clunky. Pixelmator gets a lot of things right; it's fast, has a clean UI and supports a raft of layer blending types. But it lacks a lot of useful keyboard shortcuts-and I don't mean "Photoshop shortcuts", I mean shortcuts, period.
This in itself slowed me down considerably; I have a small set of Actions in PS that I use for some final tweaks on most images. Having to re-create those layers manually, for each image, isn't that fun.
I would definitely say that for most users, Pixelmator (or Acorn, etc.) can definitely replace Photoshop. But it's difficult to move away from PS when there's such a large ecosystem attached to it (as unfortunate as that realisation may be).