[mLuby]

1) It's the only static non-rocket launch system. As such it doesn't require people to buy into the "active support structure" concept which is a prerequisite for orbital rings (<3), launch loops, or space fountains. (Rotovators, though arguably static, require exotic setups for terrestrial use.)

2) It's been around long enough to have made it into mainstream culture, especially via big-budget Hollywood movies.

3) The name is straightforward and approachable to laypeople. An elevator to space nicely obscures issues like its mind-boggling size, duration of transit, and even "reach space" vs "achieve orbit."

4) Picturing the structure fixed over a point on Earth seemingly sidesteps sovereign territory issues and international cooperation, further simplifying the conversation.

The Space Elevator is a gateway to megastructures more than a gateway to space.