What's the point in SF4 on 3DS? What's the point of any fighting game, without local multiplayer? Racers and shooters too. Your personal preference, many people are happy with online multiplayer or even single player for these genres.

Some people only own an iPad for mobile Minecraft. Some people only own system X for game Y... you can claim that hollow argument to any combination: somewhere on this planet could be a couple of strange people that buy a system for only one game. 

Switch will have mobile minecraft with local multiplayer. Oh, has Microsoft announced Minecraft for the Switch? And they announced even local multiplayer for that version? That's great! Do you have an URL for that or did you just made that up?

Having to go back 30-40 years kind of proves my point of how consoles have moved away from being the 'arcades at home'.

The point about the extra controller is that back in NES/SNES days, the 'extra/premium' bundle would be a second controller. These days it's bigger hard drives, faster processor, free subscription. Nintendo is going 'backwards' again (Wii Tennis/Pong). It's good when Nintendo goes 'back'.

Mobile, portable multiplayer is the hook this time, software-wise. Having 2 controllers as standard is like having motion included with every system as opposed to buying a motion plus addon. The multiplayer userbase is equal to the console userbase. On a home system it isn't a huge issue but for a portable?

Pokemon Go and Mario run are all about getting the game into people's hands so they move up to dedicated game systems. A second controller does exactly that. No more DVD-tutorials for Mario Galaxy, instead you can hop in and out at will. More important is that normal people would rather play local multi than alone. Who plays alone when someone else is sat next to you? Even people you don't know, like at the arcades. What's the point in SF4 on 3DS? What's the point of any fighting game, without local multiplayer? Racers and shooters too.

Some people only own an iPad for mobile Minecraft. Switch will have mobile minecraft with local multiplayer. I know people who only buy Playstation for local FIFA. That's close to £400 on the PS4 v £250 for the 4player Switch version, and again, it's portable. People have been willing to buy gimped mobile versions for years, now they're ungimped and local multiplayer is standard. I expect most devs to 'tack on' a multiplayer mode just like they did with motion control however I think there is a much bigger chance of striking gold with tacked on multi v motion. Wii tennis without motion control is Pong. Street Fighter without local multiplayer is........a boring practice mode.