Are people buying other brands of printers?
"Or are people buying other brands of printers, just not HP printers, perhaps? I don't know... it's a question, not a comment."
In the days of relatively small monitors with poor resolution I would often print out emails, word processing documents or sections of documentation to refer to while working.
Wide screens with better resolutions mean that I can now read a full PDF page without having to enlarge it then scroll within a page. I can also have an editor, word processor or spreadsheet alongside that PDF, and my need for much of the printing I traditionally did simply disappeared.
Added to that I switched to a mono laser back in 2009, It has not only been a lot cheaper to run than an inkjet but it doesn't do all that fussing around cleaning print heads before starting to print. If I really need colour printing there are plenty of print shops around who possess far better kit than I can afford and will do that at a reasonable price.
My choice of mono laser in 2009? Simple: The nicely compact Brother model I chose had an OS X Compatible logo on it. The (ugly and bulky by comparison) HP models only claimed to support Windows, which fact, incidentally, was a complete surprise to the salesman who was trying to push the HP kit.
With respect to an earlier comment about HP printer drivers' limited support of Windows versions, that Brother has worked with all versions of OS X from 10.4 to 10.11, and certainly more than a couple of versions of Windows.
What printing do I do nowadays? Apart from correspondence with my local town hall and the tax office, the last few letters I printed were cancellation notices for ISPs and other online services I no longer required.