Considering you said you think the PS4 version will hit 1 million week one, I'm inferring that you're suggesting the PS4 version will outsell the 3DS version?

I don't think it will do anything to the ps4 version.  Regardless of other platforms there are a lot of DQ fans on Playstation this gen. 3DS ain't eating them. 

Yes.

I certainly hope you're right, but why don't you think that the 18 million gap in install-base will be too much to overcome? Games like Monster Hunter XX and Yokai Watch 3 have easliy outsold the best-selling PS4 games despite franchise-fatigue and a lack of innovation from yearly outputs, clearly the 3DS still has enough life left in it for DQXI to hit at least 2 million? After all, we've seen Pokemon hit 3.5 not so long ago..

In Japan, yes, it will. 3DS has more DQ games than PS4. 

It's not going to eat it and lately ps4 has gotten more of the actual new DQ games then 3DS. I'm not talking old titles ported.  

I think 3DS version sells more but it won't eat the ps4 version.  That will still do very well. 

of course will sell amazing. Even Switch version will cross the million mark. The point is: 3Ds userbase is bigger, DQ VII, VIII, IX, X and Jokers series was on it. PS4 will have best version though, and I think a lot of people will buy both versions

Why not as a win-win result? for example,if PS4 version do 1 million while 3ds sold 1.5 million,its still a successful to Square Enix and Sony I guess.

And Nintendo, of course.

That was my point.  Nobody is eating anybody.  Sony,  Nintendo and SE all win.