And a lot of TV creators are glad to have shorter seasons, and so are a lot of viewers. 26-episode seasons had a lot of padding, a lot of weak or pointless episodes that were just there to meet a quota. Producers had to rush to get something on the air to fill the slots, and thus often had to settle for shooting scripts that didn't work. A 26-episode season might not have had much more than 13 episodes that were really worthwhile. Shorter seasons allow more time to refine the ideas and to focus on the best ones.
And no, the norm is not 10 episodes, except on a lot of cable shows. Network shows still tend to have a minimum of 13 episodes per season, usually 22 or more.