to add to that, 'awhile' is probably a chunk of a few years at least in my opinion.
There's still crap that needs to be cleaned up in the ministry and other major organizations/industries that the Order probably doesn't feel comfortable letting anyone else handle, and I don't think that Voldemort was the only problem they were focused on -- primarily, yeah, but there are other things they feel like they need to stick around to fix by themselves.
I have a character that was in the Order while the war was going on and right afterwards, and that question was brought up then too, but I think that's sorta the general consensus we came to with admin. ^^