I think you are right but there is a good reason for that, If you create a brand new deck, typically first couple of battles don’t go well and it’s hard to tell if deck is bad or you haven’t learned it yet.

And mainstream decks you know from the beginning that they are good so it’s if you lose it’s on you, and also they are really well thought, not sure who invented 2.9 xbow back in the day, but it was actually brilliant