We can surmise or guess all we want. Resources at Auctiva's end are scarce. trace routes alone indicate how slow everything is at that end compared to the rest of the route.
There is likely enormous packet loss and quality of service issues that relate to the type of local network at Auctiva's end.
Suffice it to say that it is costly to improve the network (and the hardware) to handle the traffic. So at busier times it is almost impossible to get through. (do a search on packet loss and that will explain a lot of what is happening on the network access side).
When Auctiva was purchased by alibaba I think we all felt a change in the corporate culture and caring. This is a profit center for auctiva and there is no reason for them to sink more money into it.
We can moan and try to help solve the problems by guessing what and how many issues there are or just accept reality. More money to improve the network and response times is not likely to happen.