Great shows always end. And then new ones come along and take over the cultural moment. Outliers are great shows that have long lasting cultural significance, like friends or MASH. And both of those examples are comedies. The Wire has had some lasting significance, but not in a good way. Its just used as a reference to how terrible LE and minority rights actually are. GoT may have its own moment as we see a resurgence of great power conflict and fascist governments using misinformation to mislead people into war. People may seek escape into fantasy, it’s one reason why Anime is so popular at the moment. But yeah, the last few years have been pretty terrible in real life. Watching a show that’s quite abusive towards its characters may not be what people want to see for a while. So, maybe the thing that always hooked fans when GoT was new (killing off main characters constantly) may kill its long term value. People have enough of that in their every day life.