I'm always thinking it as an energy problem. Using up energy to suck up carbon isn't 100% efficient, and tech to suck up oil isn't either. So trying to undo the damages of the latter, we produce even more CO2 (building those and also running those ( even just by supplying remote areas with stuff)) and then use up valuable energy, so we can just go on ignoring that we're burning up a limited resource without much efficiency to start with.