Re: Just a matter of timing
"Something *like* this is almost inevitable, since toy drones prove that existing batteries have the necessary power-to-weight ratio"
Modern batteries do have good power-to-weight ratios. However, the energy-to-weight ratios are still complete shite compared to liquid hydrocarbons. Sure, you could build a battery powered airliner that has enough power to fly _for_a_few_minutes_ before you run out of energy.
"better battery technologies are always on the horizon,"
Maybe you've never noticed this, but _the_horizon_never_gets_here_.