Coal was mostly crushed in the 1980s by the low capital cost of
https://en.wikipedia.org/wiki/Combined_cycle_power_plant
and the low cost of gas of Natural gas in the US and UK, the latter because of the discovery of petroleum in the North Sea. The same economic steamroller pushed "pause" on nuclear energy.
Today we see coal miners in the US who are empowered by the "one state, two votes" structure of the Senate to keep the industry alive despite it being basically uneconomic as well as environmentally unsound, the difference is this time the coal miners are supported by the right instead of the left.
Those who hate Thatcher today aren't so much pining away for the way things used to be but instead for the loss of their dreams for how they think things could have been.
Thatcher's most memorable slogan was "There is no alternative" and it's that sense that the realm of the possible in politics shrunk dramatically is why people have a sense of loss. (I'm amused that both Angela Merkel and Hillary Clinton liked that slogan too.)