It's not the lenght of the season, it is the scheduling. If I can get a good show that can run 6 to 8 weeks at a time without a break I am happy. It seems, today, you will get 3 or 4 episodes, then some type of interruption one week or two, then 3 or 4 more episodes, then break for the holidays, etc...
I think a series as they are being called these days, in place of season, should be 13 to 26 episodes.