If we couldn't do it quickly and couldn't make an even quicker buck on it, we lost interest. In the end we took the safe, economically thrifty route. We sent probes and they sent home pictures. The couch potato generation played interplanetary tourist. There were a lot of good reasons to get off this ball of mud spinning in space, with pollution and population pressures heading the list.
Gravity is a wonderful thing, but the lack of it has benefits as well.
Chemical reactions, for example. Drugs and chemicals impossible to manufacture under gravity could be made in space. Consider metals blended in space, strange new alloys, foamed metals. But the investments were never made, the future of mankind stagnated, the stars slipped out of our grasp. In the end it was only a token effort.