. . because they had no competition.

Canon made the print engines but was forbidden by contract from making an HP compatible. Canon still sold a bunch of printers (cheaper than HP) that needed special drivers, and people had endless problems with the drivers and lack of software support.

This spoiled the market for all other laser printers, all of which were HP compatible because they weren't restricted by contract. HP could ask any price for their printers because the customers wouldn't buy anything else. I will never forgive HP for being the only vendor ever to force me to buy "grey market".

When Canon developed the high resolution engine used in the HP Laserjet 4, they showed it to HP and said, "If you don't let us off the compatibility clause, we will not sell this engine to you, but we will sell it to everyone else". Without an up-to-date engine, HP was out of the printer business, so they caved, and that's when they had to start to compete.

It's been downhill since then, but it takes a long time for a monopoly like that to fall. The decline has been helped along by small dealers as pissed off at them as I was and by big dealers pissed that magins for HP product approached 0 (but not as a limit).