The reason is that it's too expansive - it would mean we stop whatever we're doing and focus almost all resources on this for decades. If the price wasn't an i

The reason is that it's too expansive - it would mean we stop whatever we're doing and focus almost all resources on this for decades. If the price wasn't an issue then there are simpler ways to deal with global warming without building anything - just consume less. But we're not doing that cause it's politically unpopular. So any solution that relies on majority of people making huge sacrifices probably won't fly either.