This will get confirmed closer to the date, due to low cancellation charges. However, one needs to know whether there is some festival at the destination of the traveller.
When I see such waitlists, I try and see the Panchang of that area to see whether there is any festival or auspicious occasion, such as marriages/religious events which causes such high waitlists not getting cleared.
But the main reason is blocking tickets when cancellation charge is only Rs 40 and Rs 70 for confirmed tickets. This is one area where PRS booking comes...
more... into play. IRCTC agents who book etickets cannot afford to do this for etickets or i-tickets, because cost of holding these tickets is too high, given the margins, and how can an IRCTC online agent locate customers, unless he has very good contacts. But combination of both is possible.
I am aware that I am an agent myself !
Good wishes.