Very unlikely, but I expecting it will hit around 120m.

Dunno why you're making 60 million a magic number.

I never said that being #1 was all there was to it, so back off with the snark.  What matters is how much they're making off the XBox division, and how much they could make by investing that money in other business ventures.  Microsoft has been moving to more of a focus to games on windows, and the guys who were passionate about the division aren't heading the company anymore.  Since Microsoft lumps the XBox One with the 360, the surface and a few other things, it's hard to tell how much they're making or losing.  They cited the division as an issue in 2015, and hardware sales haven't seen a huge rise since then.  Revenue has decreased since last year what with price cuts and all.  Microsoft's been pretty low key regarding XBox's results which seems to indicate they're nothing to write home about.

And no, Microsoft isn't going to be ok with it as long as they're making money.  Even if they're making 50 or 100 million a year, that might not be enough to keep the division worthwhile.  Because they may be able to make 2 or 300 million by investing that money somewhere else within the company.  

If I judged based on the consoles that came before the Wii, then why would I expect the Wii to sell 100 million?  Why would I have expected the PS3 to sell under 100 million?  Why would I expect the 3DS to sell only 60 million over 5 years?  

Past results can be useful, but using them as the sole determinent of whether a console will be successful is ridiculous.  That's basically the Pachter method of prediction.  Without knowing what the NX will be, guessing that it will be a failure, or sell less than 60 million is just a random guess.

There are too many variables to determine anything is a sure thing at the moment.  And that's all I have to say about that.

Basically this. 

Also if we keep stretching the definition of what PS4 is (4K, 8K and so on) of course it's bound to cross certain barriers in the end.

I don't think so

Not a chance. It would be amazing if it did, but it won't.

I'm fairly confident it'll pass the PS3 and I personally think it could probably surpass the PS1 as well.

You'll be lucky to see PS4 + XB1 + Wii U hit 155 million by end of 2019.

PS4 itself? Not a chance. PS4 plus PSNeo? I still see it galling short as many (including myself) will not waste money on a slightly stronger version of the same console.

If they release a 3rd upgrade of the PS4, I could see a total number eventually reaching it.

LoL, there have who think that it will sell less than the PS3 ?, at this rate the PS4, will sell nearly in the PS3's Level, until January 2018.

Consoles don't stop of selling after a succesor came out, they still sell throught the Years, Xbox 360, and PS3, despite several years in the market still sold well after PS4, and Xbox One's Launch, Console's Life-Cicle in sales don't finish until the Company stop making the Product, not when the Next console came out.

The PS2, had 12-13 years of sales, PS3, is going to the 10th year, PS1, had 10 years of Market, PS4, will likely have 10 or more years before the end of the Life-cicle.

Not happening