Space will be economically uninteresting until somebody manages to drop the price-per-pound by a few orders of magnitude, and then an awful lot of things becoming economically interesting. A viable space elevator might just accomplish that.
I can't see the cost of delivering and supporting humans in space dropping below the cost of, say, delivering and supporting humans underwater in SCUBA gear. Living in a space hab is like living in a deep-sea hab in many logistical ways (including no need for decompression time).
The only major uses of SCUBA I'm aware of are 1) the military; 2) mineral exploration; and 3) tourism. Is there really any reason to think there will be "an awful lot" of other economically interesting things to do in space?
Mine some asteroids for iron, carbon, silicon, water. Now you have the raw materials for the biggest solar powerplant ever made. Ship the power down the space elevator and you have cheap renewable energy without the downsides of it being earthbound. Ship any excess ores down to earth for more profit. Some of those asteroids could have billions, if not trillions of tons of raw materials ready to use.
It's a bit far out there as ideas go, but so was visiting the moon at one point!
But you don't have to send people. There's lots of stuff in space that can be done by robots. Easier than in the deep sea, because of easier communicaton.
And if you're not talking about the deep sea, but fairly shallow seas, then doing things there isn't really all that expensive at all, and driving the costs of operating in space down to that level is going to be incredibly attractive.