Yes, ideas change - UESPA vs. Starfleet - but a willingness to overlook continuity is not great storytelling. That's all I was getting at. Respect your previous work, think about retcons, and decide when to use them, don't just let new writers change things because they're too lazy or know so little about your world that they just make up things that contradict previously-established 'facts'.
But there's a difference between ignoring previously established "continuity" when a show first debuts and changing a premise once that show becomes more popular. Take M*A*S*H for example. In the first few seasons things were established that were changed later in the series (i.e. such things as Hawkeye's home state first being Vermont but later changed to Maine; Blake's wife first being named Mildred and later changed to Lorraine, and numerous other examples). Most of the early MASH continuity was later changed to suit the writers when the show started becoming popular.
MASH had the distinction of being on the air for 11 years and gaining popularity each year, while TOS was only on for 3, and was NEVER popular in its original broadcast. Unlike MASH, TOS never really had the time to truly nail down how things were actually established in their universe. With hindsight now that Star Trek has become a cultural icon, sometimes we lose sight of the fact that in 1966, NO ONE who worked on the show ever took this stuff anywhere near as seriously as we do.