While I have no doubt there are those who try this, any such patent they obtain would be invalid on the basis of the “Prior art” doctrine.
The patent trolls are looking for situations where they can tie up a company in legal proceedings. Even if you can claim prior art, you still have to go to court and prove it. That gets expensive in both time and money. When the cost to fight exceeds the cost to settle, the bean-counters can make a strong case for buying off the patent troll.