If the MAX stays grounded until the end of this year, which is quite likely, then with current production rates and the number already sitting on the ground, we could be looking at nearly 700 aircraft parked.
Many airlines would be unable to have all their aircraft on the ground at their home base at the same time due to lack of space and rely on the fact that most of the time they will be in the air or turning around at out stations.
The MAXs already in service at the start of the grounding are reasonably well dispersed worldwide, however with the number already produced since they stopped flying and 40-50 more coming out of the factory doors each month, where are Boeing going to store them ?