5M consoles sold in Japan?

Say hello to Monster Hunter 6 and Dragon Quest XII ... for iPhone 8. Hope you like touch controls. 

Nintendo doesn't need Sony's third parties on their handheld... they'd benefit little from the deal. Sony had given up on handhelds so it would be a killer win and many system selling franchises over xbox for the price of just a few hand held games.

And by the end of the gen, I wouldn't be surprised if Nintendo was the only one of the big three to have made profit. Sony and Microsoft have lost more money than they made by going into the gaming industry. Nintendo always wins.

U still didn't answer, doesn't developing games on PS4/5 defeat the purpose of Nintendo making unified devices?

No I don't think so. 

It only defeats the purpose if Nintendo is planning to make a direct competitor to the PS5, which I don't think they are (Nintendo already missed their chance to compete head-on with the PS4). 

I don't think honestly Nintendo even wants to make that type of system. 

If the Nintendo hardware is simply just a handheld and there's a home variant of it that allows the same games to be played on TV ... that's not really a threat to Sony. It would be like saying the Vita TV/Playstation TV is a threat to XBox One ... two very different products. 

That can be a fun little family/kids-focused device that Nintendo specializes in and it can have some dildo controller (lol) from Miyamoto or whatever wacky new idea he has and serve a different function in the market. I think Sony would be supportive of that.

Even in the Fusion/unified platform setup, I don't think the home variant is going to be a huge seller. I'm thinking it's a device that'll sell somewhere in the 15-20 million range, most people investing in the Fusion platform will opt for the handheld. 

Honestly... How does this really benefit Nintendo in the long run? I see a lot of win for Sony... Not so much for Nintendo.

- 100-150 million console users to sell their games to instead of 15 million. 

- 100-150 million console users to sell Amiibos to ... instead of 15 million

- Added developer support for their handheld, probable chain reaction of other Sony-centic third parties throwing more support behind HDS/Fusion. 

- Solid tech partner to experiment in with a gaming phone or VR if they feel like it.

- Marketing support (look at how much Sony supported Destiny). 

- Unified Japanese market = stronger Japanese market. This is good for Nintendo. 

I would say this would double the sales of a game like Zelda and increase the reach of their amiibo toy sales hugely as well and put Nintendo in a much stronger position to counter the negative impact of smartphones/tablets (which are the real enemy IMO, Sony is not and hasn't been for a while). 

That's not what I mean, the point of this unified approach is so that they can develop all games on one platform and increase their output, this helps with lowering R&D costs significantly while maximizing software profits and allows them to branch out and make more new ip by not having  to make 2 versions of each series. If they start developing games for Playstation 5 which will have much higher development costs/time along with their unified platforms which will undoubtedly have higher dev time/costs than 3DS,  they are in an even worse position than they are now. They will have to make 2 seperate Mario Karts/Smash Bros/Zeldas/Mario platformers/etc still and that takes away from developing games on their own hardware which completely defeats the purpose.

The unified devices will have 1st party droughts and considering that 1st party titles are the main driving force of Nintendo devices, the hardware sales will suffer from it. U keep saying smartphones are a threat to Nintendo's handhelds, well if Nintendo isn't able to pump out enough games at a fast enough rate than they are just making it easier for people to jump ship to smart devices.

What does Sony get out of this? Looking at PS4 sales I don't think they need any support from Nintendo.

Sony don't even support their own handheld.