You do have some good points. It seems like the UK had some big economic problems. In Austria and Germany, where I know the figures, electrification was a big success.
The efficiency of a modern power plant is not 20% though - Austria's most recent coal plant goes up to 35% and CCPP (gas turbine+steam turbine) plants go up to 55%!
Besides, Austria is on 78% hydro power, with a 85-90% efficiency, just as Switzerland (don't know any figures for Germany).
Right now Austria tries (to some extent) to increase the renewable energies by building huge wind farms (several megawatts each), steam power plants fired with wood chips, saw dust, grass cuttings, sewage gas,... things that have grown in the forest or meadow and would have gotten dumped otherwise.
Regarding the gypsum issue... in the gypsum the acids are bound and can't get out, so it's a lot better than blowing them out the chimney!
Smoke filtering and scrubbing technologies have really advanced in the last 15 years. Half of Vienna is heated from waste burning and pollution is less than that of most industrial cities.
Regarding the locos themselves: early Austrian electric locos usually had a transmission like the steam locos, and AC motors run on transformers with several taps.
