bgriff

Since the whole original problem with MQDs was precisely that Delta doesn't know how much you spend on partner airline tickets, I strongly suspect that the number of MQDs awarded on partner flights has more to do with how much partners are willing to pay Delta for the issuance of SkyMiles on their flights. That is after all why every partner earns a slightly different number of miles.

There are exceptions to this rule: Korean hasn't earned any MQMs for a while now because Delta was (ultimately successfully) trying to bully them into a JV, and perhaps the automatic Group 1 placement of JV partners doesn't depend on a negotiation -- though Delta earns a lot more from JV partner flights (on some routes, at least) due to the revenue sharing arrangements anyway.

But I suspect for an airline like Saudia or Vietnam, the MQD earning will only fall if those airlines notice a flood of people booking MQD-advantageous categories and thus tell Delta they're not paying as much for those categories any more, and thus Delta awards less. (I haven't studied it closely, but it's also possible, probably even likely, that the partners aren't paying a specific amount for MQDs, but they are paying a specific amount for MQMs or even RDMs, and then the proportions of the three are roughly constant across all partners. In cases where partner flights offer a good deal on earning MQDs, they typically also offer a good deal on earning RDMs, at least relative to 006-coded tickets.)


All that said, there's a good chance that the VS loophole specifically will be closed soon, since with Delta having so much control over VS, it seems likely at some point they'll be brought into the same scheme as KLM where earnings on a VS ticket are effectively the same as on a 006 ticket, regardless of marketing carrier. So I wouldn't go booking VS PE tickets for next September hoping they'll still constitute an MQD run by then...