I haven't done the homework but I've been toying with the idea of pursuing a venture building a space elevator as a post fuck-you money career move.
Someone has to do at some point. Someone has to fail at it first. If I get to the point where I don't have a job to lose, that sounds like something feasible.
My hunch is this region of the world has the geography prerequisites. A project like a space elevator also requires a certain local political condition to be in place in order to cut down regulatory risks.
If I have to build a venture, an engineering oriented one where goal post doesn't shift is a lot more in tuned with my psychological profile than a mass market agile startup.