I too was curious about this and did some deep digging. The Coast Guard changed the regulation that made it impossible to be economically practical for the barge operators to make a profit. It had to do with escape measures, fire fighting ability and lighting mainly at night which would have added a large expense. These things had to be done each night, so any place a stop over was planned, you had to have a lot of equipment. The rising fuel prices didn't help much either.
Originally, basically the barge had to stop for the night, but only needed to put out a walkway to land at each end of the barge. This was very easy to do any place they wanted to stop.