A large portion of last year's 3rd party revenue also came from Genshin Impact, which doesn't use the Epic coupons, afaik.

But imo, if Tim still has full control of his company, I doubt we'll see the free games or coupons go away soon.

If he stops giving out free games, EGS user numbers will tank.

If he stops giving out coupons, EGS 3rd party revenue outside of Genshin Impact will tank.

I don't think Tim's ego would accept these two outcomes. He'll likely continue until Fortnite's revenue is almost not enough to pay for these two things, or he's kicked out of the company. He might reduce the quality of games or the quality of the coupons to save money, but he probably wouldn't stop anytime soon.