The first 6 seasons of GOT each had 10 episodes. Then season 7 was cut down to 7 and then season 8 down to 6. I'm thinking this was done more for financial reasons and not creative reasons.
Season 8 has 6 episodes, with an average run time of 80 minutes, vs 60 minutes for earlier seasons. That equals to 8 episodes at least. So not that shorter than previous seasons.
