True, it takes a lot of energy. Some very casual browsing suggests that steam rockets to LEO are physically feasible with reasonable payloads,1 so it might be possible to create an economically viable steam-rocket system using massive solar arrays or the like to heat the water.
That would lower the marginal cost quite a bit, since the energy inputs for launching would be free; but of course the capital costs of building the whole system would be huge, and maintenance and operating costs wouldn't be cheap. And it'd be a disposable rocket, presumably, not one of these newfangled come-back-home types.
1Though the author's example is pretty big: "A three stage rocket bigger than the Saturn V could put 10 tons into LEO!"