Of course, no one ever GUARANTEED 24/7 monorail access. But the expectation is that when the parks are open, and there is a monorail track running through your lobby (in the case of the Contemp) you would be able to use the monorail for transportation. It is absurd to suggest otherwise, and it is absurd to think that this is the "legendary guest service" WDW used to claims it provides.
Disney doesn't promise anything, there are always exclusions, or rights to change hours, attractions, etc. Sometimes those changes are reasonable. Shutting down monorail access to the MK and Epcot for resort guests who paid for (for cost savings reasons or because it strains the system too much) it is not.