What if Dr. Smith had died? You know, like he was supposed to, early in the first season. Preferably painfully. What if his brain had been removed by the Invaders (the ones with the fifth dimensional spaceship) or if he had gone back to Earth with Jimmy Hapgood at the end of “Welcome Stranger”? Or he might have been trampled when Mr. Nobody had his hissy fit. All three of these episodes would have provided ample opportunity to get rid of that dastardly villain before he had the opportunity to perpetrate (in the minds of many fans) his most evil crime of all: hijacking the show from the next episode (“The Oasis”) onward. But it might not have been like you Smith-haters (and I was one as a child watching the show) might think. It probably wouldn't have been like that at all.
Let’s look at the episodes from the rest of the first season. Counting “The Oasis” there were 21 more episodes. Some could obviously have been rewritten go give Smith’s part to other characters; for example, Judy, rather than Smith, might have been susceptible to the Keeper’s hypnotic call in the “Keeper,” and Don might have been the one to release the animals from his ship in an attempt to save Judy. The same sort of rewriting might have worked for episodes such as “The Raft,” “One of Our Dogs Is Missing,” and “The Magic Mirror.”
The episodes “Return from Outer Space,” “The Sky Pirate,” “The War of the Robots,” “The Challenge,” “The Lost Civilization,” and “Follow the Leader” do not really rely on Dr. Smith to move their plots forward at all, so they would have been safe.
What about the rest of the episodes? Smith’s devious and selfish nature drives the plot in “Wish upon a Star,” “Attack of the Monster Plants,” “Ghost in Space,” “The Space Trader,” “His Majesty Smith,” “The Space Croppers,” and “All that Glitters.” That’s seven episodes it would be difficult to reimagine without a Dr. Smith to stir the pot. Even “A Change of Space” is a story more about Smith than about Will. That makes eight out of twenty-one.In other words, eight of the twenty-one episodes left would be gone, and the others from “The Oasis” on would have had to have major rewrites… two-thirds of the first season needed Dr. Smith. And most of season two just wouldn’t have happened at all. Season three might have faired a bit better, but would still have lost a number of episodes.So what would Lost in Space have been like if Smith had died? Probably a lot shorter, for a start. It probably wouldn’t have been able to butt heads successfully with Batman in season two without any character singled out as a logical source for camp silliness (but it would probably still have gone to colour). It didn’t have the budget for effects or aliens or sets like its season three nemesis, Star Trek did, either.
Maybe I was hasty; maybe season two would have worked without Smith—it just would have been Will and the Robot getting into scrapes… Wally and the Beaver lost in space. But not more of the good stuff from season one. Television was changing and people (more importantly, the networks) didn’t want the old stuff anymore.
I don’t think that dropping Dr. Smith would have given us more of the dark, atmospheric episodes of the first season. With rare (but not that rare) exceptions, that sort of episode was gone forever when the show was faced by outside competition. Dr. Smith may have saved the show; he was a popular character that was the logical choice to carry the show when it had to change in season two. In season three, he was somewhat more in the background after another major change in direction (and ratings dropped for the first time in season three—just saying), and he was rarely the central character in a story anymore.
So I’ll say it again. If Dr. Smith had been killed off, Lost in Space would probably have had a shorter run, unable to cope with the competition long enough to make it into a third season. We’d have been left with a great season one, and disappointing follow-up season… then cancellation, probably quite justly because of falling ratings.