It may not be comps but many unassigned GTY cabins. Also, the loss of cabins may be temporary and some could come back later. Inventory management happens all the time.
Not really. Toward the end of the selling cycle the sailing could be pulled altogether meaning that it's full enough that RCI doesn't want to sell any more cabins.
The 5/24 Radiance sailing is cheap (assuming she's not affected by propulsion issues).
The 6/3 Voyager sailing also has decent pricing.
rci_sales_event_USD.pdf (rccl.com)
The price and description should be (or will be) in the planner. If not available yet, use the web tool hack to see the excursion on another ship/date.