I think the point is, though . . . "someone else" is not filling in for those who have reached their breaking point. Hence, the plummeting attendance.
Apparently those on these boards who claims "it's always busy at Disney, there are not 'light crowd' times anymore" have been proven wrong.
I know our breaking point was breached the last trip. Too expensive for the diminished experience, large amount of closures, long wait times despite low crowds (obviously staff cut-backs), etc. Instead of every two years, we'll moving to about once every five.
Perhaps, also, one of the problems with Disney announcing all of it's new attractions years in advance means that folks are simply delaying their trips until more things are open. Maybe for 2019 it's not so much economics, but people delaying their trips until after Rise of the Resistance opens. Maybe Jan-Mar will be swamped...