Fundamentally I don't think that there's room in the RPG business to support more than a tiny number of full time professionals partly (as has been discussed) because there is too much competition by people creating RPGs for the love of it and partly because of how ludicrously cheap they are in terms of hours of entertainment per pound or dollar.
At that good value it's amazing anyone can make money out of relatively rules light RPGs. I think it's why rules heavy and metaplot dominated the 90s, and there was a massive splurge of D&D books 2e and through 3.X; if you want to hire a large staff what do your people do when you've put the books out?
That's why the post was specific about Hasbro / Wizards.
Wizards made Hasbro 46 cents of profit for every dollar of revenue in 2020. Source.
D&D saw a 33% boost in sales in 2020 alone. Source. The same source shows that D&D Beyond doubles subscriptions in 2020, and so on.
Look, this isn't about killing a golden goose, or assuming that growth like that lasts forever- but some of those profits could be put into the labor force. IMO.