I think a cartridge gets boring if it doesn't follow some story line, or if it's too comon. So if a guy is interested in super high velocity magnums, a 300 win. is probably a pretty good round, but it's possibly a case of "same old same old". On the other hand the 30-30 doesn't even follow the story line. One might get a glimer of interest if the Leverlution came up, it's a slight bit faster down range, but way outside the story line.
Sometimes a whole class of rifles or cartridges go without much of a story for some time. Lever actions would be an example of that. But they are back what with CAS shooting, people looking for stealth "black rifles" (300 rpm, and no need to flip even a sellector, better triggers). Guide rifle and the whole co-pilot thing, bumping them into the dangerous game area. Not a big story in any of those areas really, but quite a make over vs. the previous 20 years. So if you are into any of that, some cartridge, gun, whatever may turn your crank if it fits your story line and it isn't an old story.