Japan, Spain and France also have negligible oil and gas production and didn't go all-in on coal as a result. Spain is 0.32% coal and 22.5% natural gas. France is 0.31% coal and 5.7% natural gas.
All those countries grew relatively wealthy much earlier than China, so simply buying ressources like gas is much more feasible for them.
If you want a fair comparison, I would suggest looking at countries in similar economical positions (good growth, but still playing catch-up with wealthy nations) and with big coal reserves (France never really had enough in the first place, which is why going "full coal" instead of full nuclear was not even an option).
Two very good examples would be pre-1980 Germany or Poland a few decades ago, and both of those were very reliant on coal for electricity as well (even Spain was at ~40% coal for power up into the 1990s).
It's not interesting to pick countries from the time before renewables and nuclear were realistically available and ask why they didn't use them.
If you want a country with less than China's GDP per capita, how about Ukraine?
Moreover, you keep talking dispatchable power, but nothing needs that to be 60% of total generation. Daytime load is generally around twice nighttime load. That implies something like two thirds of total generation is baseload (i.e. 50% of peak load for 100% of the day), and can use nuclear for anything up to that entire amount. Only one third needs to be dispatchable/intermittent, for which you can use renewables on most days and cover the large majority of that. You should only need coal/gas/hydro/storage on days when renewable generation is low -- which should be less than half of that one third, not 60% of all generation. China has enough for that in just hydro already, but then they're burning coal anyway.
Again, I'm not arguing that China is doing extremely well regarding CO2 intensity of their electricity. My point is that they perform pretty on par with most comparable countries.
Looking at CO2 per kWh (a much better metric if you want to boil country comparisons down to a single number) you will find that they are not doing significantly worse than most nations in their weight-class (GDP wise), and in fact doing better than quite a few.
Australia, South Africa, Poland, India, Indonesia and basically all of the middle east is doing worse than them. Even rich nations with heavy renewable commitments like Germany are barely 40% lower, and this is frequently negated by higher per-capita electricity use (like it is with the US).
In my view, not many wealthy western nations are actually in a position where they can demand significant improvements from China in this metric without getting laughed at (except France, Scandinavia, Spain). If you look at nations with more than twice the GDP per capita (and a headstart in development) it is more than reasonable to demand that they be at least below 50% of (current) Chinese CO2 intensity (in my view).
I strongly believe that we see so few actual demands in this regard (and so little progress in more direct CO2 taxation schemes) because most nations realize that they live in a figurative glass house. E.g. if the whole EU was at french emission levels, we'd be much more likely to see import tariffs linked to metrics like this, effecting improvement all over the world. Pointing the fingers at China on the other hand is neither accurate nor effective.
