Well, yes, but I think you might be misunderstanding the nature of Meghan's fanbase.
They're not old school fans like, eg, younger me was with, say, The Smiths - reliably buying all their albums and singles, going to gigs, buying the merch, subscribing to the fanzine (the Smiths fanzine was a laugh a minute as I'm sure you can imagine). That is to say, I had a positive attitude towards The Smiths whereby I parted with my money to consume their content and turned up as a warm body at the gigs. This is positive, 'normal' fandom.
What Meghan has is stans. Stans are very different from fans, as the poetic genius and astute social commentator (come on, he IS) Eminem realised back in 2001. Their love is based not so much on a positive attitude towards the star, but on a parasitic relationship which easily spills into resentment. It also increasingly spills into rabid online hatred of people whom they perceive as hostile to their object of adoration.
In current year 2025, Meghan's standom (IMHO, from what I see online) is a Very Online (and therefore probably much, much smaller in actual real human terms than it appears) group of people who express their support of Meghan principally by harassing, downvoting, spreading malicious gossip about, and threatening those people whom they perceive as Meghan's enemies. This long list includes but is not limited to William, Kate, Charles, Camilla, British journalists, British YouTubers, and Royal fans.
Their time is spent therefore not on purchasing Meghan's merch and streaming her content, but on harassing the above mentioned people on the internet, and posting content about how great Meghan is by comparison. This keeps them very busy, but notably does not translate into great audience figures for Meghan, and does not, I suspect, put much coin in her pocket. It keeps her prominent online, but it's not a viable real world revenue stream. Nothing like it.
There's not yet been many proper rigorous academic studies of fandom vs standom but the bits and bobs I've seen on parasocial relationships backs up what I've said above. Stans are rabid, but there's not as many of them as there appears, and they tend not to spend actual money supporting their idol, because for a number of social/psychological reasons, they don't have much money to part with.