The two biggest TV shows of the past five years are The Walking Dead and Game of Thrones. I watch a significant amount of TV, but I don't watch either of them. Why not? Because of their subject matter, mainly. Horror and fantasy are areas that have never held much interest for me. Obviously these shows aren't only about those things, but those are the genres they are based in.
Today there's more TV available to us than ever, emanating from more sources than ever. If you're old enough, you remember what it was like when there were only the three broadcast networks: a few shows stood out, but most were just average, because there weren't any alternatives. The lack of choice meant the networks weren't under any pressure to offer better shows. People either watched one of the Big Three, or they didn't watch.
The explosion of original programming has coincided with a "golden age" of high-quality TV, and creators have more options. They can aim for a niche or for broad appeal. There is so much TV it's impossible to see all of it, which is totally okay. There are plenty of choices to satisfy the tastes of all viewers. Your only limits are your provider, your budget, and your free time.