The story of The Lorax has never felt right to me. Either the Once-ler is the most short-sighted whatsit in the world, next to the Lorax himself (or at least the forest creatures), or the entire tale is a buried parable on the importance of stable property rights. Given Seuss’s general lack of subtlety when making a political point, the latter probably isn’t the case. In any event, why does no one preserve the Truffula trees? If the Once-ler owns the forest, and his business is based on the Truffula trees, why on earth would he practice clear-cutting?
He, like pretty much every other private timber company that owns the forest they log, has an incentive to preserve the forest (unless he’s renting it from the creatures, but that doesn’t seem to be the case) – clearly the Once-ler needed to fire his business planner. Or, once the land had been deforested, should have sold it and the seed to another logging concern.
Heck, they’d probably seek him out, since Truffula trees are a hot commodity, and there’s a lot of Thneedians; we already know that one of the characters is a budding entrepreneur, it’d be a lot easier and a lot more profitable for him to replant the forest than find a way to sell air. Evidently the Thneedians don’t understand marginal utility, but that’s okay, what gets me is how Seuss (and the movie) stacks the odds in his favor.