If you want to continue to develop new versions, you need enough to pay as many engineers as you need to do that. If you're not developing new versions then the money from sponsors will eventually stop.
And they used the AI bad get out of jail free card when a lot of their drop in sales probably comes from shadcn/ui and others which offer something similar for free.
shadcn is built on top of Tailwind. If Tailwind dies, so does shadcn.