A movie can end with a cowboy riding off into the sunset and leave it open for a next movie. The scene was dumb and campy. The movie didn't need the scene to leave it open for another movie.
I don't want to give anything away to people who have not seen it yet, like you just did lol, but continuing with what that scene hints at would be dumb. I'm not against what you said happening, but I think it could take another direction easily as well. One with the path of what the first two films had.