We really enjoyed our cruise on Renaissance Cruises.
It is true they started with a model that only did direct bookings, but modified that later.
They were also very ahead of the trend with no smoking. Also adults only. They had charter flights to the French Polynesia, which was one of my all time favorite cruises. The ships were also very nice at the time, perfect size. Azamara and Oceania were a direct results of Renaissance cruise line.
IMO they were innovative. Perhaps you are right that they would have gone bankrupt anyway, but I believe it was 911.
Hated that they went bankrupt when I had an open booking.