I really don't think we're very far off in our opinions, just looking at things from different angles.
When I say "robust" I'm excluding apps like OO/SO - those are full-blown enterprise apps - and damn good ones. As to Linux playing catch-up, just look at hardware driver support for keyboards, mice, scanners and even fundamental components like GPUs. nVidia has done a pretty good job of supplying tools for Linux for its cards but it still isn't a seamless integration with xorg. Matter of fact Xorg has a long way to go in supporting multi-function mice and keyboards without the user having dig into the configuration files and heavy use of prayer.
As far as application ware, I'm going to stick to photo/image manipulation software as this is a photographic oriented forum. The problem, IMO, with the native linux apps is frankly the UI looks like the front of a Techtronix Modular Oscilloscope. That's all fine and great for engineers and those that like to tinker, but frustratingly complex for those of us (who very well may be extremely tech savvy) that just want to get the damn job done. Do they work? Yes. If you have the time, patience and inclination to tweak everything out, which in some cases means opening up an XML or other configuration file and manually editing settings. I got back into photography in part to get away from my computer, not spend even more time sitting at it.
If you need some literal examples just download a trial copy of LightZone for Linux and compare its UI to that of any of the opensource solutions. I'm a bit ticked off at LZ right now as they have some support issues that need to be addressed; but even with its problems it is light years ahead of the OSS crowd in both form and function.
What I'm talking about is Ease of Use here. And the majority of Linux apps are still far too "geek" oriented to be commercially viable at any level - regardless of who controls what distribution channels. If MS was to implode today, Apple not Linux would rise to the top.
I'm not saying Linux will
ever eclipse MS or Apple, or even that it should try. What I am saying is that even with all of its advances over the past five years or so it isn't even on the same continent. The fact is it can't as long as it relies on the under funded, freelance, opensource hobbiest (or bored professional) community to build it - and this has nothing to do with distribution channels.
I use Linux as my primary workstation OS, and have for over a year now, because for the type of work I do (web server backend programming) it makes sense and there are now enough useable tools built for Linux that it is feasible. And I still have dual boot set up for XP on a separate hard drive and run VirtualBox as well. But if I wasn't an IT guy I'd still be running XP because despite its failings there are literally ten times as many options for software and hardware.