Good price but I got the Pro controller and the game as a bundle just now using the code for £89.99. Works out better if you need/want the Pro controller - makes the game and controller £45 each.
There isn't a way of justifying how Nintendo price their games but they seem to get away with it so good on them I guess
if the games weren't worth it they wouldn't sell at this price, why would they reduce them and make less money. Its worth remembering they don't flood the market with a new iteration of the same game every year or 2, you buy once. And could probably sell second hand in 10 years for most of your money back.
Released 2 years ago and still £42.99 is seen as a good price.. Nintendo are awful in that sense