Because if you don't want to play that "boring racing game" there wasn't a reason to buy a switch 2. Almost every launch title was an upgrade of a switch 1 title, or was available on something else. Mario Kart World was the unique game until Bananza came out

You overestimate LoZ's popularity and underestimate Mario Kart's. Not even those two particular entries, but in general. And I say that despite being a sucker for both the LoZ series and the less conventional BotW/TotK.

BotW sold a lot for a Zelda game and even then it sold a lot less than Mario Kart 8 DX (despite it being a port of an older game).

My take though? I got the bundle mostly because I expected better from MK World. It's not a complete dud, but I would agree it's rather underwhelming. MK8 is still my favourite and I would never consider it "a boring racing game" in any way.

Because what else are you playing on Switch 2 if not Mario Kart World?

It's kind of the only real Switch 2 game, honestly a weird launch situation. Feels odd to buy a switch 2 without Mario Kart. BOTW is cool and the updates are nice but I can play that mostly fine on the legacy switch.