How affordable would commercial travel by airliner be if each plane was used for only one flight?

That, in essence, is what always has been done for satellite launches, and explains why SpaceX continues to work on reusable rocket boosters.

Lower cost launches presumably would enable lower-cost end user services such as Internet access. So SpaceX sees a reusable booster as a “pivotal breakthrough” to substantially reduce the cost of space access by perhaps 100 times, SpaceX believes.

Though SpaceX is focusing on a broader issue, namely space travel, the innovations it hopes to commercialize will directly lower the cost of launching fleets of communication satellites to provide Internet access.