
And parks were rarely closed due to capacity so it really wasn't a problem.
The point of the reservation system is to move guests into parks that are "slow" so guests will spend money there and Disney can staff evenly across the board (although clearly minimally too). The reservation system is of no benefit to guests.
None of our trips (5) or any time I check for availability (often) were we ever locked out of every park. A couple times MK was not available but became available as we got closer.
Currently we have availability at all parks, all days the remainder of the year. We have even been offered bonus days.