Upon coming to this conclusion, I have found that I've just straight up given up on space. Someday some species may colonize another planet. I just don't think it'll be the homo sapiens, at least not while I'm around. Leave it up to the foundation of the long now. They're the ones I have any semblance of hope in. At least they've got the right mindset.
There's an old joke that, if we'd found oil on the moon, we'd have colonized it in a heartbeat.
Putting aside the absurdity of finding large stores of organic material on the moon, the point is still valid. People usually need an economically viable return on investment before funding such big outlays. It's actually pretty remarkable that our government funded manned space exploration to the extent that it did. And, absent the space race with Russia -- and its military motives -- I wonder if it ever would have.
At the end of the day, I'm perhaps a tiny bit more optimistic than you are about the future of space exploration. But let me reemphasize "tiny." I don't think anything dramatic is going to happen in our lifetimes. And, cynically, I don't think anything short of a tangible ecological disaster of epic proportions, or a second militarized space race with, say, China, is going to get us off our butts.
It's telling that even Star Trek, that most optimistic of sci-fi series, didn't set the dawn of serious space exploration until after a World War 3.
2) Manufacturing medicines, alloys, and materials that can only be produced in micro-gravity.
3) Protecting humanity against social breakdown and/or extinction in case of massive asteroid strike / global pandemic / etc.
4) Because every dollar that has been spent on space development in the US has put $7 back into the economy by way of spinoffs, technical advances, etc.
3) is far fetched and would be catastrophic regardless, and 1) may not be viable because the 15 days of the month where the far side of the moon is facing the sun, it isn't facing the earth. If placed on the other side, 50% of the month, earth would be blocking out the sun on the moon's surface, and the other 50% of the month, the near side of the moon wouldn't be facing the sun.