I'd bet a substantial amount of money that eventually he will play the part for another pile of money. Probably not for a few years though unless other work dries up. It's not like he was making Friends level money or would ever make anything like those actors make even today in residuals.
Just takes a story set in the future after the events of GoT and a desire for more spending money. Articles mention his net worth being around 10-15m, which is enough to never work if you're content living a upper middle class life... but not enough to really live anything remotely extravagantly.