I don't think expectations for non-DQ or FF MMOs were ever to sell over a million. Very few ever have, especially in Japan alone. Same with WoW, it'll be the only MMO to be that successful ever.
Obviously not. But since FFXI, SE has tried to get the larger fanbase of their biggest franchises to become MMO players. Before FFIX/X/XI were released Sakaguchi went as far as to say that after X (which introduced Play Online support to the series) there probably wouldn't be any FF without some kind of internet functionality. Instead FFXII was an offline MMORPG like and FFXIII didn't even have DLC (but only one controllable character at any time).
The MMO strategy largely backfired even though in hindsight XI became the most profitable FF ever. At the time it was perceived to be a flop and I think the ultimate aim would still be to have a combination of mass market sales and subscriber's fees. As that hasn't worked out so far the planned "everything internet" approach was scaled back but they never gave up trying to popularize it.
Thus we got FFs that looked more and more like MMOs (surely to get people used to what they intended to sell to them later) but avoided the internet stigma itself. Now with the latest entries SE has come back to their earlier attempt to turn these two franchises into MMOs.
DQX and FFXIV should support each other to grow acceptance for this type of game. As did MH and DQIX with their offline multplayer. The original online MH series also saw steady growth and still can grow larger.
That MMOs are on the decline on PCs and WW doesn't mean that they can't become a hit in Japan and on consoles. At least SE are still banking on such a thing otherwise they wouldn't pour so many resources into FFXIV.
I'm not sure what the state of DQ10 is right now, because I haven't played it since September, but we know for sure that the game already recouped development costs, so now it seems like a matter of retaining the subscriber base more than anything else. If it's bleeding subscribers, then they need to figure out how to stop that from happening.
As this type of game keeps generating development costs saying it has recouped those costs can't be a definitive statement.
I don't think losing subscribers would have to be such a big problem if it also had a constant influx of new players (and people coming back for big updates). Since the DQ fanbase is still much larger than what DQX has already sold to. DQX needs to be a hot topic and generate good word of mouth. Kid's hours could be a good way to ensure the game has a presence and catches more people's attention.
And they're now selling the game for 3800 yen and have a free 1 week trial so they definitely try to keep selling the game to new players. You can buy 180 day subscriptions with special bonus items as well, which could be due to frequent loss of subscribers after a few months. On the other hand the game itself is so cheap now that even including the 180 days subscription it's a normal price for a high budget RPG so it would appeal to reluctant old players who tried it for the free rental and then liked it enough to spend the price they're used to.
The third big update didn't cause any commotions comparable to the first two but servers are still pretty lively. On the other hand during the valentine event only about 170 000 player characters completed the event quest on the day with the most participants (Saturday) so I'm not sure if there are anywhere near 400 000 active players, much less subscribers.
I still think that SE were aiming for considerable growth over FFXI with DQX and FFXIV. Since the console market is losing so many customers to social games having the remaining gamers concentrate on a few titles from their strongest brands seems like the best idea to focus their investments.
Instead FFXIV did terribly on PCs. DQX did decently so far but the SE quote from the other thread indicates that they're still expecting more.