Or maybe they have an agreement with whatever power claims that part of the galaxy not to go there.
As for Daniels, I can't think of any indication on his part that the Federation doesn't exist anymore. Didn't he even say it would fight the Spherebuilders together with the Xindi when he and Archer were on that future Enterprise? (I can't remember what time that was supposed to be, though.) There are plenty of monuments to things that still exist so that isn't proof of anything. Obviously, the Federation of Daniel's time would have evolved and changed from that of Archer's time so that he might think of the latter as a thing of the past, just as I would about the older incarnations of the European Union.