All three companies have a reliable base of 10-20 million people that will eventually buy their hardware regardless of alternatives on the market, just for the first-party exclusives. So from that line of thinking, even with only GameCube-level market penetration with a post-Wii U console, Nintendo will still be a profitable company. The other two I think will be fine as well.

Sony is now a division of Apple.

Nintendo now makes Mario App games for a Nintendo Tablet (which is both portable and home console)

Microsoft owns the living room with yearly Halos.

I think that Nintendo and Sony will both be a lot smaller than they are now, with Nintendo being a lot more software focused and Sony being a lot more music/movie/gaming focused and less hi-fi.
MS will also be more or less software based allround and will, along with the other two, struggle to compete in the crucial casual and handheld markets (the handheld market will likely be mostly tab-like and phone-like gaming then, pure handheld gaming devices like the 3DS will be obsolete.
The home console market will probably become less and less relevant as technology fuses together in multimedia devices across the market and globe.

They will all stick to what they know until the market turns into something they wont know, this will be make or break for them all and they need to ride the wave or drown, this is especially true for gaming. Nintendo and Sony appear to be set up for the worst ride of the three, Sony are dead broke, losing marketshare and whole divisions and markets and Nintendo will likely never be able to become relevant on the gadget/phone/tablet scene, they just don't have that kind of pedigree and being a gaming only company might actually hurt them in the long run.

to many factors to make a prediction, but i only agree with the MS prediction, and i doubt they'll get into film, but they do need to branch out somehow.

Sony returns to it's former glory and the big 3 becomes the big 1.

I doubt that this next console generation will be the last. The fact is that as long as each console has good exclusive IP's, people have a reason to buy the hardware.

by 2020 nintendo will be selling games with holographic tech, and getting involved into virtual reality... Yep, play mario as mario, samus as samus (yay) can wait to play DOA on it!

And another thread where you over estimate microsoft and underestimate sony

Stealth troll alert.

User was warned for this post - Radishhead

Microsoft will still be here but will be focusing on a all around entertainment system

Sony will be back to there former glory and up to the playstation 6

Nintendo will focus on handheld devices

Microsoft -- invests billions into its own SPARTAN-II program in the hope of creating a corps of super soldiers that will be stationed in every American living room to ensure consumers are playing on their Xbox 2880 around the clock. Unemployment in the United States reaches an all-time high.

Sony -- while doing research for Gran Turismo 10, Sony developers uncover the secret to immortality in an abandoned hover-car factory in the ruins of Old Detroit. In customary fashion, Sony executives choose to advertise the magical elixer with a 23-minute abstract live-action commercial.

Nintendo -- famed developer and Earth hero Shigeru Miyamoto, who famously deflected an asteroid from hitting the planet in 2017 with only a Virtual Boy, leads the Nintendo faithful to the New Kyoto colony on the far side of Alpha Centauri. There they live in peace growing root vegetables and playing Wii R, the first true virtual reality system.