Only the Franklin bypassed that protection by her wormhole error in her warpdrive, ending up despaceing inside the perimeter.
But Jaylah's ship got there somehow, too. And countless others, supposedly. Starfleet had not dared try until they got the tech, but possibly others were more advanced or more daring? I doubt wormholes took all of them there unless the place is a wormhole magnet.
(And we
can pretend it's not if we decide that only
Franklin ever ended up there via wormhole, and that the universe provided millions of years in which a wormhole incident could deliver a ship there, and trillions of ships to which this could happen. It would not be
that big a coincidence in the Trek version of reality, then. But it happening to more than one ship would flip the scales and dictate the "magnet" scenario.)
I guess the big question here is, did the
Franklin wormhole herself directly to that mountaintop, or did she initially just pop into existence inside the rubble sphere and for whatever reason then land on the mountain?
The former scenario certainly calls for far more precision from the wormhole than the latter. While we can postulate e.g. that the wormhole automatically collapses at the vicinity of solid bedrock, this doesn't explain why the ship is undamaged and perfectly level. OTOH, controlled landing doesn't explain why Edison didn't take off again, or why there's a heap of not-so-loose dirt covering the ship.
Krall stranding several shiploads of people there is terrible, but risking the safety of the Enterprise-A to re-enter the region? probably not.
I dunno. The
Franklin, decisively lacking in modern navigation gear, got through the rubble just fine. So did millions of spacecraft under Krall's command. And the original interpretation that the place was a traffic hazard may have hinged on the loss of the Magellan probes - but we can now deduce they were not lost to traffic hazards but to Krall.
The Feds do place quite a bit of faith on their probes, even though crewed starships seem to survive challenges robots do not. Failure to have probes return was quoted as the reason why the Great Barrier was supposed to be an obstacle, wasn't it?
That savanger society is unlikely to band together, or have enough left of the races technology to do anything with either that or the Enterprise remains. And should then even cobble together a ship, it might not survive the nebula, and they'd arrive at Yorktown that is maybe a century or more advanced than it is now and able to fend them off.
OTOH, how many of Krall's victims are "savagers"? Nice folks like Jaylah's might form the majority of the population, and they'd have put significant distance between themselves and the immediate vicinity of Krall's base that is the location of all the surface action in the movie.
Plus, savagery might be the result of the planet being inescapable. But inescapability was primarily the result of Krall's evil siege, and with news of Krall's departure spreading, soon the planet would be a cornucopia rather than an oubliette - anybody could command the remaining drones to build escape ships or latinum palaces instead of war machines. Or, at the very least, to lend a ride to the other side of the rubble field in one of the droneships.
Timo Saloniemi