It's not as easy as you think, especially since Lexmark refuses to provide even basic tools to get it done. (They say they provide a toolkit to write Linux drivers, but it doesn't work ... as one person put it ... even if you knew how to use the toolkit it wouldn't help you any)
That's probably true. But I bet it would be possible, even if it was a lot of hard work. I figure the first thing to do would be to install the printer on a Windows computer, and then watch the control sentences the software spews out to the spooler. If you have a basic knowlege of how other print software works, this will probably be easier, because you will probably see sentences you recognize. From there it is just a matter of writing a 2way interpreter for the sentences into some basic control language that the target OS's spooler can understand.
Unfortunately, any of the above would probably find you at odds with the hardware/software license agreement, and Lexmark could, in theory, have you shot.
So, the only reason certain bits of hardware don't work in Linux is that nobody has the time or the desire to handle the risk and build the driver. Eventually, though, someone will get around to it. Might be a hundred years from now, but I'm sure it will get done.