I have had printer calls where the printer - Lanier, Ricoh, HP etc worked in XP but not in Windows 7 and there were no drivers after they upgraded the OS. Other models may have a universal driver or say go to the Microsoft Update site to get a driver. It sometimes works but they will have to get a new printer when it does not.
I think these guys get together and figure how to boost sales.
Fortunately most laser printers out there will work just fine with HP drivers - the LaserJet 4 used to be my goto, but since it was discontinued after XP I've since switched to the LJ 5200 PCL driver. It typically doesn't matter what brand the printer is, HP drivers seem to have a 'keep it simple' reliability to them.
It can be quite a process to get some printers to work under Linux as well, and which can vary from one flavor to another: http://forums.opensuse.org/showthread.php/475015-new-user-cannot-get-lexmark-z700-p700 -work-2
But thank God for computers in general, and what an OS can enable for good.