For the Fiscal Year that lasts through March 2018? Factoring in the different versions, digital sales, and possibility of an international release? Probably.
DQ9 may have had the luxury of being released on the DS, but the 3DS has almost outsold the PS2 in Japan. Even if we account for the smaller install base, that should easily be over 3.0 million on the 3DS alone this year. Factor in the New 2DS XL being launched and bundled alongside the game, and it should be higher.
The console version won't sell as well, but should still be impressive. Final Fantasy XIII sold to about 40% of Japanese PS3 owners back in 2009, and Dragon Quest should be at least as big despite the recent lack of major console releases. And the PS4 in 2017 is healthier than the PS3 was in 2009, at least in Japan, with more consoles already sold and more related PS4 games released (FFXV, Persona 5, DQ Heroes, etc). Factor in the bundle, and that should be 1.5 million or more.
This admittedly adds up to a bit less than 5 million, but doesn't factor in unknowns such as the Switch port, an international release, etc. Dragon Quest games seem to take roughly 8 to 12 months to get localized nowadays unless they're remakes of 7/8 on 3DS. This makes an international release before spring unlikely, though a February/March release is conceivable, and would likely sell maybe slightly less than a million copies. A Switch version would be at least as lucrative, and would likely be ready in time for Q4 2017. Unreal 4 already supports the Switch, and Square Enix has shown interest in the platform. Even as a somewhat late port, DQ11 could find a comfortable home on the Switch, especially with bundles. And the Switch is doing fairly well in Japan thus far.
