For example I think the style changes in TOS season 3 were influnced by 'what was popular' (ie Batman); and it's one reason they didn't have an issue with the more campy aspects of a lot od Sreason 3; as it was scene as 'popular' by the TV industry of the time.
They took that approach with the third season of "The Man From U.N.C.L.E.", i.e., going for more campy stuff, and it damned near killed the show. They switched back to more serious stuff for the fourth season, but by then the damage had been done and they got canceled.