Another idea: due to the incident with Marle, the pendant, and the Gate, most people think that the Telepod is yet another one of Lucca's failures. This steers the development of technology away from teleportation and towards locomotion.
EDIT: Remember, the transition from the pure Lavos timeline to Keystone 1 wasn't a single jump. By the time the party even reaches the future, they've gone through two or three timelines. The timeline at that point includes the Telepod accident. The pure Lavos timeline may have had successful Telepod technology - and thus more survivors.