While I agree that the show declines noticeable in seasons 6 and 7.... it was still solid TV. It wasn't incredible like it was...but still solid.Despite not sticking the landing during its final season, Game of Thrones was fantastic television for a very long time. Indeed as soon as they ran out of books, it all went down hill. But that was after about 5 fantastic seasons.
I think what really kills GoT for me is how incredibly rushed the final season (number 8) was....and it did not have to be. This is not your classic "we are getting cancelled got to wrap this up". HBO is literally going "please showrunners, make more, we will give you money...you like money right....have some money". They had every green light to make a longer season, or hell 2 or 3 more seasons if they wanted.
But the showrunners said no they could do it in just a handful of episodes....and they were so rushed it felt like absolute hot garbage. Now I can respect that the guys were tired, or maybe wanted to do something else, or had a new opportunity, etc....these things happen. But you turn the reigns over to someone else, wish them good luck, and let the project continue...you don't just kill it so you can be over and done with it.
GoT is such a travesty for that reason. It rose so high, and fell incredibly far in that last season. Season 7 had its bad moments believe me....but it was still really enjoyable. Season 8 is watching your favorite toy get thrown into a garbage fire.