rough77 you gotta ask yourself, is it more important for the developers of PR to spend their time working on reviving older maps, or make totally new maps that we've never seen before?
There's also the fact that some of the mappers who've made those older maps, might not even be part of the PR community or don't have the editor files anymore.
You can't blame the developers as a group for not maintaining older maps. That's something to bring up with the individual mapper of the specific map you want revived. The PR devs have said over and over that they'll gladly include older maps, but only if they're upgraded to work with the current version of PR. So, if the original mapper doesn't want to polish his creation, to have it included in new versions, there is little the developers can do about it.
Also, I'm not 100% sure about this, but I think the devs allow server admins to run any maps they want. Old or new. It's just that if servers started throwing in maps that most people don't actually have anymore, people would start complaining about having to download extra maps. Server admins tend to want to make it as easy as possible for people to join their server.
to create a PR map... hours, days, MONTH I guess
I'd like to see anyone create a good quality map in under a month.(without working 15hr days for the whole month) Even a 1km map. It would be my guess that most 2km+ maps would take close to a year to get to a point where it can be released.
Mapping is like developing a video game, in the sense that it's possible to create the worlds greatest game, that has full details in ever aspect. But, the problem is, it wouldn't run on anything short of a super computer. So, game designers have to sacrifice things here and there, to streamline it into something usable.
It's the same with mapping, anyone could start in the corner of a 4km map, and put in every little detail, making it the best map possible, with underground subway systems, sewers, full of custom objects, sounds, sky, the whole lot. But, the only problem is that you'd be working on it for 10 years.
My point is that no map is ever complete. It just gets to a point where it's playable and the mapper is happy enough with it to be released. So, I doubt very highly someone who doesn't have a lot of time invested in a map (ie. not the original mapper) would want to spend their time on improving somebody's old map. Because, that's time they could be working on their own map(s). Time is a valuable resource when it comes to editing maps.