That seems like a silly way to do the calculation vs CO2 sequestration tech would only be built where you could get very cheap and low CO2 energy.

Generally the idea is convert to cheaper and cleaner energy AND THEN focus on CO2 removal as well, not build CO2 removal powered by a coal power plant.

As long as we can keep the price trending down direct CO2 removal has SOME potential and shouldn't be overlooked, but we may need larger scale riskier biological based CO2 sequestration boosts as well. Doing nothing is still biological sequestration into the oceans, acidification and potential major collapse of ocean food chains... so it's worth trying to push the tech forward.

CO2 removal will always be needed on Earth because CO2 levels are not naturally stable and modern humanity can't survive the natural cycles of +10 and -10 degree changes that natural life survived. CO2 might be a convenient way to control Earth's temps long term. We are clearly great at adding it to the atmosphere, it only makes sense to keep researching how to remove it.

Maybe it won't pay off for 50 years, but that's still how technology and research works, it's not all short term rewards and it's not mostly success stories, it's far more like banging out every possibility until you find the one that works.