[ZeroGravitas]

But since 2/3rd of the fossil energy is wasted, it's more like 40% of the useful energy.

Some people don't know about the primary energy fallacy, others know about it and try to exploit it, so you should be suspicious of the opinions of anyone trying to use it suggest lack of progress and futility.

[leonidasrup]

If you measure useful energy as electricity output of a fossil fuel plant then yes. But in many cases the waste heat is used in other applications for example district heating or low grade industrial heat.

If you use fossil fuel to directly drive an industrial process, for example melting of ores/metals/glass then the efficiency is much higher.

[jbrnh]

Electricity can still be more efficient for many of these with heat pumps, like indoor heating and steam production. The gap is smaller then for working engines of cause.

[red75prime]

Who talks about futility? It's about tradeoffs: seasonal storage/nuclear power, batteries/wind+interconnections and so on.