The argument for declining pax on the route is laughable. The reasons why we have seen a slow decline in pax number is that,
1. They have gone from 5 to 3 flights a day
2. They have messed the timings around and
3. They have reduced the size of the aircraft.
Each time this has happened they have seen a drop in pax numbers.
Agreed there are other factors but these are the main ones.
If you don't believe me check the pax figures before the embraers came onto the route!