The author looks at primary energy and despairs as the needle only moved by 3 percentage points to renewables. Also the author tells us that energy-saving gains are of no use.
Those two statements are absolutely contradictory. In general, the public does not seem to understand primary energy well enough to make informed decisions.
If you just transition to renewable (or nuclear) electricity production and ignore everything else, you cut primary energy use of electricity generation by 30-60% just by the way that primary energy use is calculated. A thermal power plant wastes at least 30% of its energy as waste heat, about 60% if you don't do residential heating.
A solar panel by definition converts all its primary energy input to electricity. Even with nuclear energy, you take the heat output of the nuclear process as primary energy, inflating the primary energy by about 200%
With combustion car engines it is the same. If you electrify those cars, the primary energy use drops as gasoline combustion engines waste 60% of the energy in the oil as heat. Losses in your batteries and power generation also add up, but at 60% losses as benchmark, you can even break even with current fossil electricity generation.
Look at houses: If you build a modern passive home, the heat output of the human body (approx 100W) becomes significant for calculations. Ambient solar irradiation (i.e. light that shines through your windows and gets trapped) delivers most of the heat. Both these energy sources will not appear in any primary energy statistics.
You can put this even more over the top and include sunlight trapped by photosynthesis as well as natural heating delivered by the sun in the energy used by agriculture. But then all of human energy consumption will become a rounding error. But psychologically it might sound nicer if you think that we only have to transition away from the 0.01% or something of human fossil energy use. This sounds ridiculous, but this is essentially the same argument the author makes.
All of these examples show that the imperative to curb our fossil energy use should be (regardless of whether you advocate for nuclear or not) should indeed be "energy efficiency". But energy efficiency does not mean cutting your TV energy consumption by ten percent or something. Energy efficiency means reducing our "balance sheet" by electrification, avoiding energy conversion losses, and reducing energy use for heat by using ambient energy.