I think that's because we've made it politically difficult to build transmission. In the United States, you have to get approval from every jurisdiction and landowner along the route, so valuable transmission lines are politically impossible to build. (See: SOO Green, Grain Belt Express, BECI, other planned lines).

Oil and gas pipelines are centrally approved by FERC, so there is no such difficulty. It doesn't have to be so difficult to build transmission, and it would unlock a lot of wind and solar development.

Whenever wires don't make sense, as is the case for aircraft, synthetic liquid fuels can make sense. In a world where the inputs are free, the inefficiency of the process is not relevant.