There were attempts to convert the staterooms on the SS United States into time-share condos in the early 1980’s.
Time and again investor groups looked various options for the ship-including a Queen Mary type hotel. But the ship was just too run-down to do anything. I believe there was also going to be a major expense in removing all of the asbestos on board.
Ship is gutted, asbestos is removed, which really precludes the conversion to a hotel - there's nothing left of the original furnishings (or even the propellers, those were all donated...)
Problem with converting it into a time share is that stateroom bulkheads are part of the structure of the ship, it would take a major undertaking to re-structure the internal skeleton to support it. Without any of the furnishings, the attractiveness of a retro-cruise or hotel is gone and far too expensive to replicate.
It is a US flagged ship, so it'd be fine for use for domestic cruises, but the rooms are smaller than most desire, plus of the three sister ships which were converted, only one remains in domestic cruise service in Hawaii, and even that might be pulled by the end of the year.
It is not suitable for a floating museum as there's nothing to exhibit without pulling from the museums and collections that have the fittings...
Honestly, the only thing I can see this as being suited for is a floating university - it's gutted so converting it would be easy, the small rooms would work well for dorms, the common rooms would work well for classes, and shockingly, the engines are extremely well maintained. Aside from fitting out the ship, it would require making new props and it would be good to go.
Alternately, it could be fitted out as a floating immigration port to bring over all those 'refugees' from Europe, processing them during travel.
Anything else, really, just doesn't work.