LOST Theories

The ALT Explanation
Your Name Hugo's father.
Theory I'm a long time reader but first time poster, so be generous. Also, if this has been posted before, then sorry, whatever.

Throughout the most of the sixth season, my view on the ALT timeline was that we were seeing flashforwards. I thought that the 'reset' hadn't happened yet and they would find a way to reset things, causing the island to sink. However, my theory has changed. I still believe my original theory to be possible, but my new one makes much more sense.

What we are currently seeing in the ALT timeline is the lives of the losties if they had they never been touched by Jacob. That is the simple part. The part that confused me is how would that have resulted in the island being sunk? I put some thought into it.

If the losties had never been touched by Jacob, they would have never gone to the island. If they never went to the island, they never would have gone back in time to the 1970's. If they were never in the 1970's, then they never would have dropped the bomb in the season 5 finale. I think the reason the island sunk was NOT because they set off the bomb, in fact the bomb was the thing that stopped it from sinking. Instead the incident (the pocket of energy) sunk the island. If the losties never went to the island, the island would have sunk.

In other words, Jack was trying to make it to where they never landed on the island by blowing up the bomb, but instead it was the only reason the island remained intact.

I know this theory has flaws (IE if jacob never touched Locke, how is he still alive after falling seven stories) so please add on to this.