Once it was announced, I was expecting the new Fire Emblem Echoes to be a dual release, 3DS and Switch. It seems to be using the Awakening engine and it would have been a waste not releasing it on the 3DS, alongside Awakening and Fates. But why wasn't it on the Switch too? It would have been a pretty good game for its first couple of months. And people would have bought it, Fire Emblem now is not the risky franchise it was before, it doesn't need an established userbase to sell well. Was it due to lack of time/profit to port the engine to the Switch?

Who knows? Its Nintendo...

Its releasing in may so I guess it was late in development for them to ... switch... consoles. Tho they are developing a FF for Switch, so you know. All the same for me.

I just hope its more like Awakening and less like Fates in terms of characters and Story. I wasnt a big fan of Fates.

Why isn't it cross buy 3ds/switch. Sony does it with Vita and PS4 and Microsoft with Xbox and PC, it's good customer friendly move. 

I think it probably has to do with the graphic, Nintendo would not want to advertise a new game for switch with 3DS graphic and also the game was designed for Dual screen vs Switch single screen. 

Who knows, maybe the engine being used is way to limited to show better visuals on the switch and would need a lot of programming and time to enhance it on the switch.

What will be more troubling is if the Switch release gets a 3DS downgrade like the "Warriors" titles and Mario Maker/Smash/Yoshi. I'm starting to smell some stink behind the unified platform logic.

Either Nintendo is being careful not to kill the 3DS in fear of Switch's failure... or they intend on having a separate portable line. To me, the entire reason for creating a hybrid was to be able to devote all teams to same platform. If they keep diverting resources to 3DS ports, they are killing the major business angle of the Switch.

The 3DS will be gone soon, I'm guessing these are titles that were already long in development for the 3DS.

Two reasons come to mind:

1) it was already mostly done and the gap in power between 3DS and Switch is rather large.

2) They don't want to try and merge both console and handheld out of the gate since the 299 price is a bit steep for handheld only audiences so they want to phase it out more slowly and a new FE based on essentially the exact same engine as the one they just made is a fairly easy option to take.

I personally never thought that the Switch would come out and immediately all 3DS everything would die immediately; the Switch was always going to be too pricey to try and force the 3DS crowd to migrate over immediately. No, they aren't going to make that move until 1) they have the price down a bit, probably 250 and 2) they have major franchises in place to immediately give a compelling reason to make the jump. I am looking at mid 2018 as the probably point at which such a move will be made, based on the target window for Fire Emblem Switch.

Also, they will want to give Pokemon Sun and Moon time to breath and finish getting the bulk of its sales and also give Game Freak time to work on a Pokemon project for the Switch.

Switch is getting it's own game as is 3DS. I don't see the problem :/

Because that would increase development costs, it would mean the first main series FE on Switch is only a remake and Nintendo needs to keep releasing 3DS content until the Switch has gained a big enough install base to become profitable on its own.