He doesn't hold a majority.
> And the big plan that the opposition has is: to go to the EU, negotiate the same exact deal that has been voted down 4 times, and then whip their MPs to vote it down again.
No it isn't. The plan of the opposition is to get an extension, and hold a general election as a proxy for what should happen: Tory party for no deal fuck you up the arse brexit, Lib Dems for revoke it and put out the fire, Labour for a 2nd referendum with clear options that involves significantly less self-mutilation than an empty "leave" deal.