Where are they taking D&D where there's little other competition, though? Novels, PC or console or app-store games, films, miniatures, toys; those are hardly uncompetitive markets.
They are, and they aren't. Specifically, those area all places where competition is not simple "win/lose".
When I go to the market to buy a bag of flour, I'm going to buy only one bag - one company gets the sale, the other does not.
When I go to the movies to see a film, I may pick one for right now, but that does not preclude me from seeing another film later. I can go to the movies lots of times.
So, in some places it is not necessary to "crush the competition" to succeed. The competition can do just fine, and you can succeed too. RPGs are already somewhat like this. When you step out into fiction, computer or mobile games, and so on, you are talking about a much, much larger potential market, and again, your sales are not neatly precluded by another's. With limited resources, you compete where you are likely to make the most money, not merely against what one originally thinks of as your "competitors".
And, if we want to go pie-in-the-sky, if D&D comes out with a good movie that nets a profit of several hundred million dollars, all the PnP sales will look like diddly by comparison, hardly worth considering in the grand scheme of things. Crushing Paizo in RPG book sales won't even be on the radar then.