Yeah, it's hard for writers to do that without a big upfront commitment from the studio. Typically they only get one season assured, if that. And then if the show catches an audience, suddenly the studio flips and demands the writers string it out into extra seasons.

We all know shows that started out strong then got ruined by this stuff, like Lost or Heros. Or the internet's favorite punching bag, Game of Thrones.

I think The Wire is an interesting exception. They never got more than a single season commitment, but still managed to make something that feels cohesive over 5 seasons. They did it by using an ensemble cast where character's arcs can be extended in later seasons, but with new characters entering the mix as well. They also picked a different theme for each season, looking at the failures of american institutions from different directions, and resolving that theme within each single season. The result is each season feels distinct and can stand alone, but they also form a cohesive whole.