About a year ago, I became quite a bit more active... I had been sending off QSL cards to these stations through the ARRL Outgoing QSL bureau... I have sent out over 200 cards. To date, maybe I have received about 10 back.
You haven't allowed nearly enough time to get a significant return via the DX Bureaus.
The Outgoing QSL Service batches the cards by country-of-destination ... so it can be quite some time until they've accumulated enough cards to send a package to some locations. (And BTW, there's just one
ARRL staffer, along with her volunteer husband who sometimes lends a hand, to handle the thousands of outgoing cards.)
Likewise, on the other side, the Incoming Bureau at the DX location waits until it receives enough cards for each individual operator to make it worthwhile to send him/her a package. And then that operator can wait quite a while until he/she accumulates enough cards to make it worthwhile to send a package for shipment Stateside.
Upon receipt back here in the States, it takes time for the volunteers who staff the Incoming Bureaus to get around to sorting the incoming packages, and then wait until a sufficient number of cards accumulate to make it worthwhile to send a package to you.
So the 1-year turn-around using the Bureau both ways that you've gotten for that handful of cards actually is quite quick.