Pokemon Sw/Sh sold 16 million copies worldwide but player scores have been consistently low and we aw greater backlash this gen than any other
Sales of DLC will reflect player retention and overall attitude towards the game they purchased
How bad do you expect the DLC to perform?
How do you expect Nintendo to crack the whip at Gamefreak when sales for the DLC don't compare to the 16 million?

If even normie players can see the game isn't complete and was bad, they're not likely to want to spend even more money to make the game feel slightly less incomplete.