Doc O'Leary schrieb:

I’m not counting them out, but when the topic is cost/efficiency, the
basic question is still how much energy is being expended to get each
kg into orbit.

At the moment, not at all. Ballpark calculation:

An older version of a Falcon 9 reportedly had 488 tons of total
fuel, 147 of it RP-1 (a modified kerosene). Liquid oxygen is
quite cheap, and if we give RP-1 a cost of 1 dollar per kg,
we probably are in the right ballpark. So, around 150 000 Dollar
per launch.

This is _very_ low compared to all the other costs. A launch
cost around 50 to 60 million dollars now, if I remember the
figures right.