I'm relating my own subjective and personal experience - so obviously I can't speak for people who may have just started last year or the year before that. I'm speaking solely about myself and my own relationship with the game. People can start or stop playing for any reason, though; from it not being their cup of tea to their friend group moving on or whatever. I will tell you one thing I've found in my own anecdotal experience (again, limited solely to me) having played the game since the Classic Beta and on into Shadowlands: the number of truly new players seems very low to me. I know a handful of people who started playing in TBC, and even more who started during WotLK, but almost no one who started in Cata on into WoD, Legion, or BfA. Plenty of returning players, sure; people who played back in what I consider WoW's heyday but left for a variety of reasons, but almost no one who began playing in the past couple of years.
Do they exist? I'm sure they do - but the numbers seem very small compared to veterans like myself or even those who are on-again and off-again from back in the day. And my story isn't going to be everyone's story in any case, I was just relating my own tale of melancholy and nostalgia related to what WoW once was and is today - which for me is a mix of good and bad, things missed and things enjoyed still.