Would a mountain lion push hogs off? From what you indicated, the hogs were pushed off by flooding. The question is more of why aren't they returning?
In reading numerous discussion on mountain lions and hearing landowners speak, they don't push off the deer, but decimate them. A mountain lion will destroy a local "herd" of deer in a very short period of time and take years to recover, they say. I would assume that just like with human hunting putting pressure on hogs, a mountain lion could dissuade hogs from being around for a while, but they should still be coming back. Hunting doesn't keep all hogs away forever and it becomes a maintenance process. Keep in mind that mountain lions roam over a fairly large area, the lion would apparently being pushing the hogs out of dozens of square miles, if not hundreds and will be gone from parts of its range for weeks at a time, and that just isn't likely that the cat pushed all the hogs away where they all stay away for such long periods. If the cat is pushing around the hogs, then it would be likely that hogs would also get pushed into your area as well as the cat makes its rounds. Is that happening? It doesn't sound like it.
With that said, folks in some other flooded areas have reported hogs slow to return as well, though I don't imagine that will last. We also know that hogs can disappear from an area for periods of time, depending on resources. "Where did the hogs go?" is a common online query on various hunting forums. In the fall, the common response is that the hogs have gone back into the woods for acorns and other mast and no longer hit the feeders. If we were smart, we would fill our feeders with acorns and not corn, LOL.
The issue probably isn't just as simple as a mountain lion, though a lion could figure into it. You lost your hogs due to the flooding. Hogs have been slow to return to some flooded areas. A big cat may temporarily hinder a full or quick return.