You're not missing anything, your R3000 is supported by Apple (see list
). If your printer is not in the list and the manufacturer doesn't offer drivers then CUPS/Gutenprint might be the solution.
The whole CUPS mention drove me off.
OS X uses CUPS as it's base print system, so it is no matter what it's a "supported" printer or a child of a lesser God.
Beside that I sleep well and maybe print even better