That is sort of the issue. The economics of the situation make it not really possible. You'd have to make space - space that wouldn't be used for something else. As was mentioned, the people napping aren't spending money - except on the room to nap. And it would be expensive - the rooms would need to be cleaned between each guest. In an airport which is mainly serving adult business travelers - its $30 an hour. Add in the issues with kids (bed wetting, damage to rooms, the need for additional staffing) and you are probably looking at $40 an hour at a minimum to cover costs and some profit.
Plus there is the liability issue - if any abuse were to happen in those sleeping rooms, Disney would have huge liability and PR issues. If people use them for sex - again, big PR issues - if anyone involved in the sex is under the age of consent - we are back to liability issues -
can you imagine what the conventions of teenaged cheerleaders could be like