Hmm... I didn't expect this at all. It seems to me that whenever a large technology-oriented company gets in trouble, they always go after their own paying customers, saying anything they can to make their angry customers feel like it's somehow their faults.
I'm glad to see HP repent, but we all know they'll try something like this again. Other manufacturers are likely to follow suit.
This may be my own overactive skepticism speaking, but I'm willing to bet HP will conveniently "forget" to update a large number of it's printers. I'm also willing to be HP will take it's sweet time with these updates, so that the users will be forced to buy at least a few cartridges before they can go back to their generic cartridges.
PS: I would love it if someone (maybe Epson or Brother) would design a printer with a free (as in freedom) firmware. Then the FOSS community could jump in and improve whatever they feel needs improving. If the firmware was free (as in freedom), there would never be any temptation to lock users into name-brand ink. But, that's probably never going to happen.