I think bottom line is that it is too expensive and therefore not sustainable to settle or explore space much further either funded through taxation, private fundraising or speculative investment. If launch costs come down and other technology makes it easier then either public or private efforts can do it. In terms of speculative investment... I agree there is no prospect for financial returns on any reasonable time frame so things like asteroid mining are not going to attract large investment until the math checks. And there is no business case to be made for investors to fund the settling the moon or mars or anywhere else. But neither is there a real case to be made to the public. Space exploration was the first thing to get axed in the 1970s when the US couldn't afford it. And the likelihood is that there will be additional times where funding for space exploration from the government coffers just won't be viable. Space exploration as a point of national pride only works for missions that can begin and end in a decade or so.