The issue is, honestly, the free-rider effect. It's too difficult for an entrepreneur to get paid unless they resolve a specific problem in such a way that they can demonstrate value to a customer. The only thing that will generally make money is impact mitigation, because they can sell it to an affected buyer. At least, as a general rule.

With government-driven carbon reduction requirements feeding into a trading market it might get to the point that there's enough money to warrant huge investments in sequestration. But I'm not optimistic that capitalism-driven countries will want to impose a high enough cost to spur that kind of investment. At least, they haven't up until this point.