First, each vacation home is owned privately, and has rates set by the individual owner. There really isn't any notion of a single "season calendar" for vacation homes. For our typical week (which is Peak season at Disney), some homeowners have low-season rates, and others have high-season rates. An owner of 1-3 properties isn't always as plugged in to how demand changes over the course of the year as is Disney, with their 28,000 hotel rooms.
Also, the WDW Resort experience is so very different from the vacation home experience that the two markets may well be quite distinct.