Season 1s are great, setup, some payoff, a bit of lead into the overarching story. Then season 2 to X. The heroes win and then lose in the final episode, cliffhanger to next season. People get bored. Final season is announced and they wrap up the show.
As far as I’m concerned, that show ended when the first season did (which corresponded with the ending of the book).
When I heard a season 2 was happening, I thought it might be based around the book’s epilogue. Instead, it’s the same story dragged out long past where it was supposed to end.