I think we've been in this artificially low fossil fuel price environment since the beginning though: the externalities aren't priced in.

The thing is, abundant cheap energy will make it less and less worth doing.

One way or another, it will definitely be stopped. At some point, civilization collapse would end the burning of fossil fuels at scale. The question is at what point it will stop and whether any tipping points are passed which accelerate the process out of control.

It's far from obvious that all efforts to limit carbon emissions will fail and to say otherwise is deeply cynical. Measures are being taken already. They are not enough to reach the claimed goals and the claimed goals will probably not be reached, but that's very different from saying warming will not be stopped at all, let alone "of course". More measures will follow once the adverse effects get worse in industrialized countries (e.g. deaths and economic damage due to changing climate and weather events).

I won't happen by magic. Even with their ever increasing scarcity, as long as no alternative exists, they will be economical.

If all the fossil fuel is burned, we will probably never reach that point ; society breakdown will happen sooner.