He did -- at least in the version of 1977 that we saw. However, in the original timeline -- which may or may not be the same as the one we saw in "The Incident" -- both Ben and his dad stayed on the island beyond that point. In the original timeline, Roger died on the island during the Purge, personally gassed by Ben. That happened well after 1977.
More and more, I'm not convinced that the explosion of Jughead's detonator changed anything -- or even that it actually exploded. It was a nuclear device, but it was a detonator, not the actual bomb, and it was at the bottom of a deep hole. If it did go off, we don't really know what effect it might have had under those circumstances. I think it may be possible that simply drilling into the electromagnetic "pocket" at the Swan site might have been enough to to qualify as "The Incident."
Do we know the original purpose of The Swan? We know the orientation film said it was designed "to study and manipulate the unique electromagnetic properties" in that part of the island. Was that actually true? Radzinsky seemed to regard the plans for The Swan, and its construction, as an NSA-level state secret. Why was that? In what way did they plan to "manipulate" the electromagnetism found there, and to what end? According to Lostpedia, the EM at the Swan site was similar to that found where The Orchid was built, but was 30,000 times stronger than the latter. Considering the Orchid was right next to the frozen donkey wheel and could move the island in time and space, what sort of mind-boggling mischief could be done with the Swan's power, beyond making airliners crash at a distance?
, and/or, even report off work if it was the only option for watching my weekly episode of Lost. 
! She also told me to help me get through the day I should mentally give " Sawyer Nicknames" to everyone I come in contact with.
