This was just supposed to be the next issue of the series, like #17 or something. They just decided to relaunch it under a different name for some reason. It will last 4-5 issues, so that could count as "a while" by some definition.
Yeah this isn't supposed to be permanent. Maybe even IDW's way of doing a type of "passing the torch" story since that has been rumoured for Ghostbusters III. Maybe this is Burnham's attempt at doing his own kind of GBIII. The guys are still around, they are just part of the sub-plot now and have to figure out where they are. It's not like they're totally gone from the book. That was never the intention with this. The back up story seems like it will be neat as well...basically what happens to the ghosts that are placed in the containment unit? We've seen episodes on this of course, and the art was of the cartoon versions as well from Burnham himself. Sam Hain greets the latest arrival. I thought the issue was quite fun myself.