It's pretty clear that something fishy is going on with the ratings distributions here.
I can't think of why that would be the case, or how it makes sense.
Compare this to the Game of Thrones ratings[1], where each episode has about 3000 ratings.
The individual ratings may not be very "accurate" (well, they're going to be subjective no matter what. My favourite episode is near the bottom of its season), but the trends are interesting. The fact that the floor of seasons 1-9 is above the ceiling of season 14 and onwards (save a few outliers) reflects quite well what many fans think.