Distance from Earth would be a benefit in case of nuclear war, which currently looks highly likely at some point. Even if humans aren't eradicated, it would probably be a civilization-ending event, and not many places would be safe. However, it does seem like some kind of giant submarine might be more feasible and cheaper.
But yeah, 0.9g doesn't seem like enough of a draw to make it economically feasible.
That's absolutely correct I believe. I don't see how such a colony would be self-sustaining without some big advances in technology (at which point you might as well just build a space habitat with low gravity).
Yeah, but sadly anyplace we can send a bunch of humans to, we can figure out how to send a nuke to as well. And if leaders on the homeworld are crazy enough to turn Earth into a wasteland, I'm not sure how confident I'd be they wouldn't point their threat at your colony (which might look like an enticing bargaining chip).
Bargaining chip for what exactly? The colony wouldn't have any kind of resources, except the wealth of its residents, but that wealth would all be tied up in bank accounts back on Earth. If Earth gets turned into a wasteland, the colony will probably die because I don't see how it could possibly survive without regular supply missions from Earth, and that depends on things on Earth not getting too horrible. Also, if Earth became a literal wasteland, all the wealth those rich people on Venus had would be gone: it's just numbers in computers after all.
You're not answering the question. What concession? What do a bunch of old people in the clouds of Venus have to bargain with? What resources do they control?
They aren't bargaining with the colony, they're bargaining with the nation that sent its citizens there (or any nation that views the survival of the colony as important enough to make other concessions).
It's like a criminal that points a gun at your kid and threatens to shoot unless you do X.
But yeah, 0.9g doesn't seem like enough of a draw to make it economically feasible.