This is exactly what happened. GRRM wrote himself into a corner he hasn't been able to disentangle. And the showrunners didn't have the luxury of waiting 11 y

This is exactly what happened. GRRM wrote himself into a corner he hasn't been able to disentangle. And the showrunners didn't have the luxury of waiting 11 years between seasons. I do think they could still have done a better job, but it's hard to say from the outside because we don't know the budget, time and story constraints they were working under. By the time the final few seasons came around, almost all the actors had become famous on their own right, who were taking on a ton of other shows (and I doubt they were under contract for the entire run, especially since it was never expected to last as long as it did) and it must have been a massive challenge bringing them together to film the final few seasons.