There was a time when onsite hotel reservations were difficult to get, period. A time when getting a room at busy times had to be booked a year ahead, and you took what you could get, never mind even thinking there might be discounts available, that was a fantasy.
When 9/11 occurred followed by the economy drop, tourism took a big hit. Folks felt a crowded theme park was a terrorism target, others had no discretionary money to travel, people from other countries had more trouble traveling into the states. Disney and everybody else started discounting to get those rooms and the parks filled.
Now people have relaxed a bit, tourism is back, rooms are filling and rates are going up. Folks who weren't used to "the old days" are upset because they can't get a discount, others are astounded that rooms are sold out for the resort they want. The boost in tourism has rolled over somewhat even to DVC. In a way we have an advantage. I have never heard of someone who couldn't get a ressie if they reserved using their 11 month window. You are right, though, forfolks who can't plan ahead, DVC may not be a good idea. Frankly, for people who can't plan ahead often onsite WDW is not a good idea as it will be full and/or expensive.