That explains cheap hardware but doesn't explain why the software is as bad as it is. Amortized over any large hardware vendor's product line the per-unit cost of investment in the software has got to be nothing.
The software can only be explained by attempting to sell printers to, well, idiots. Looks pretty, doesn't work worth a crap.
HP, please, just give me an 'enterprise' driver and nothing else, that's all I need.
My experience is that hardware companies are almost universally bad at software. I can only guess it's because the hardware guys are treated like rockstars and the software guys are treated like a necessary evil.
This applies to pretty much any other computer-related thing sold to non-tech people. They either don't care or don't have the skills to judge the quality, so a better quality but more expensive product will always lose in favour of the cheapest crap.