Re: Linux on the desktop
I've generally found the "official" drivers for printers and scanners to be horribly bloated, and often poorly supported...
Linux distros generally support a lot of printers and scanners out of the box, no need to go hunting the drivers, and the built in drivers are often better than what the manufacturer provides for other platforms.
I have a couple of old HP scanners here, they have official windows (32bit only) and mac (powerpc only) drivers which are useless today, but they work out of the box on linux. To repeat your phrase, "it's certain that I'm not going to junk my working scanners, one of which I've had for more than a decade"...
On the other hand, there are standards for printers (Postscript, PCL etc), you're doing yourself a disservice if you buy a proprietary printer instead of one that supports one of these standards. I use an old laserjet which supports both postscript and pcl, and i can print to it from virtually anything, and anything i acquire in the future is still going to support postscript even if all the other crufty proprietary printer drivers are deprecated.
As for apps, most things are moving towards being delivered via a browser, either cloud hosted or hosted on a local server, and already those who actually require local applications are a niche, those who require specific local applications being an even smaller niche. Gimp may not be photoshop, but how many people run a pirated photoshop to do extremely simple operations that could have been achieved just as easily with mspaint? I know quite a few such people. Plenty of people never use msoffice for anything more than a simple letter either, libreoffice is more than adequate for the vast majority of use cases, as is google docs and the office365 webapp.
Windows didn't get where it is today by being the best or most capable tool for the job, it got there by being widely available, cheaper and more heavily marketed than the alternatives, and barely adequate for the job, the same thing will happen with chromeos if google pushes it hard enough and in many cases its better for average users (safer etc).