I have found anything hard fact, but it seems like all the older ones are on the backburner

As a math teacher here is what I think is happening.

They are reporting a median wait time, not an average wait time.

The median is a number that is in the exact middle of a list of numbers.

The numbers we are looking at are "days of waiting".

Here is what I think may be an example of how this could be working.

For an example with easy numbers lets say that there were 10,000 people on a waiting list.

Many have been waiting for an extended period of time. Say 300 days.

Then if 10,001 more apply there are now 20,001 people on the waiting list.

This means there are 10,000 old and 10,000 new and 1 NEW guy right in the middle.

If they approve all 10,001 new applicants in 3 days then that 1 NEW guy who is in the middle of the 21,001 people waiting list is the median. This "median" puts the median wait time at 3 days.

Had they 20,000 on the list the middle of the list would be a spot between the 10,000 old and the 10,000 new. Then you have to average the two middle guys to get the median position. Old guy 300 days, new guy 3 days, (300+3)/2= 151.5 median.

Hopefully all the waiters get approved soon!