Not a single country with any manufacturing and/or industry [0] to speak of [1], can just casually cut off their main hydrocarbon supplier without major consequences, nor do nuclear reactors replace such resource dependencies.

If Russia stops delivering gas, then ultimately that will translate to a higher German oil demand, as a lot of formerly gas tailored usage will be retooled to oil.

As Russia is sitting on the single largest gas supply on the planet, nearly a quarter of the worlds supply [2]. While with oil there are a few somewhat competitive non-Russian alternatives [3]

So if Russia's resources will continue to be geopolitically taboo, then a lot of Europe will shift back to oil instead of gas.

[0] https://www.energy.gov/sites/prod/files/2019/11/f68/Products...

[1] https://data.worldbank.org/indicator/NV.IND.MANF.ZS?location...

[2] https://www.worldometers.info/gas/gas-reserves-by-country/

[3] https://www.worldometers.info/gas/oil-reserves-by-country/

Going all in on nuclear wouldnt have fixed that. At least, not without an additional $2-$3 trillion spent.

The nuclear plants they shut down were a drop in the bucket compared to gas, solar and wind.