If fossil fuels are available and cheap, unburdened by the cost of their negative externalities, of course they will be chosen instead of a more expensive CO2-free alternative. That's what killed the nuclear renaissance in the US ~15 years ago.

What this means is there's low hanging fruit to solve these problems in other ways, once fossil fuels are no longer allowed to pollute without cost. There are already good ideas for solving the long term storage problem, with many of the component technologies already existing for other purposes.