The thing is - is it necessary to have the best gear to enjoy the game? As a different example - I'm sure it would cost tens of thousands of dollars to max out your characters and gear in Genshin Impact, but I've played very enjoyable 100h+ and it's perfectly fine even if you don't have the max ascended characters and gear, I have a feeling those are there basically for the wales to spend money on but aren't necessar…
Most people I know who have played Diablo would tell me their rift tier, paragon level (might be a different term in English but they play in french so that's the term I know).
So for new players, it might not be that big of a deal, but for players wanting to play more Diablo the game is telling them to cough up as much as they can