Hi Derek,
I think, the 1 to 3 hour cruises of the pleasure ships in nice landscapes are classical for younger and older passengers - also not very expensive. I remember when I was a child, the anticipated joy of a paddlesteamer cruise on Rhine river. The following trip was joyful for 1,5 to 2 hours - special for looking the engine maneuvers - but for longer time is became boring.
An adult person would be more able to appreciate the changing pictures of mountains, rocks, small old cities and so on. I don`t made a longer cruise tour until yet,
but IŽ ve heard about Danube and Rhine tours with modern cruise ships, which must be very interesting and at the same time relaxing. So I don`t think, that there is any conflict between the day cruisers and the floating hotels.
I wish all members a happy new year, a better one than 2020!