"We have already gone to Mars. Maybe Thiel thinks we should go each year?"
A bit of partisan hacking there. Obviously he was talking about efforts to establish a base, manned missions and so on. This should have been obvious checking e.g. Thiel's Founders Fund public statements at : http://foundersfund.com/the-future/#
"We believe that the shift away from backing transformational technologies and toward more cynical, incrementalist investments broke venture capital". (and more details on aerospace there).
Mars and other missions, so far, do not contain actual "transformational technologies" but "cynical, incrementalist" innovation (bigger robot, cooler landing, better mechanics). From the perspective of spaceflight economics and reliability these increments and modes revolutions do make sense. Curiosity was a big step actually considering the many new technologies involved. But Thiel is from a crowd which aims higher and more ambitious.
Or perhaps he justs desires to get better returns again from a worn out economical model in a tired world?