I wonder if--as they must have thought--Dr Smith was actually helping the show?
He certainly was. His antics were very popular. After all, it was a show whose audience was largely children.
What if he had been gotten rid of---could the level of seriousness been brought to a level between the mostly serious of TOS and the 'completely ridiculous' that it devolved into?
Well, first off, I'm not sure TOS is the right comparison, since the shows weren't trying to reach the same demographic. One was a family show, the other an adult drama.
Second, I think most of the first season
did achieve what you're talking about. Remember, the descent into sheer camp wasn't just about Dr. Smith, since it didn't happen until the second season. It was about competing with
Batman. People forget what a massive, industry-shaking hit and cultural phenomenon
Batman was in its first season. And there's always a drive in TV and movies to imitate big hits. Not only
Lost in Space but
The Man from U.N.C.L.E. got more campy in response to it and in an attempt to compete wtih it.
So without Dr. Smith, if the show had been popular enough to get a second season, it would probably still have been camped up to compete with
Batman. But conversely, if
Batman hadn't existed, then LiS
with Dr. Smith would've remained, if not serious, at least nowhere near as campy and intentionally ludicrous as it became.
Part of LIS' problem is they wrote themselves into a box. By stranding the ship planet bound everything had to come to them. In a way it was a sci-fi version of Gilligan's Island.
But it also saved them the expense of rebuilding the planet soundstage every week or showing takeoff/landing sequences regularly. Irwin Allen was famously cheap.