It already happened. Look at DS and Wii. If you mean only consoles, no way. My dad's a employee of Microsoft, and NONE of his staff members WILL EVER buy a Xbox One. F EVEN MICROSOFT EMPLOYEES DON'T WANT IT, THEN NO FREAKING WAY!!!!!!!!! Sorry for the anger, just got out of having an argument in YouTube with people saying the Xbox One will beat the PS2 with best console sales ever.

OP must live in Washington, Colorado, or DC if he thinks they'll both get 100M =/

Nope!

X1 will regain some ground in the North America and certainly improve worldwide but it will still be trailing PS4. Post holiday I'm expect a 2:1 ration globally, not to say X1 will be doing bad, PS4 will just be doing a lot better, with Europe going ape for it and Japan starting to contribute more then 7k per week X1 could never truly compete globally. I expect this to be the trend througout this whole gen, which means MS will probably drop a new system the minute they see opportunity for a new console and get in there early ( late 2017 earliest-backwards compatible).

I see at least 120m PS4 LT versus 50m-70m X1 liftetime sales depending on whether Microsoft makes it obsolete asap or allows it a 8 year life cycle without being replaced.

It really depends on how long they let this generation drag out.
I mean, this is what, year 9 for the 360? That's still not quite at 85 million yet (or at least I don't think so).
That being said, if this generation lasts 7-8 years for both, the X1 could potentially do it, though I would personally think it will fall somewhere between 60-70.

PS4, I have no doubt will pass it, probably stop at around the 120 million mark would be my guess.

Just my guesses though, so if people think I'm wrong (which I'm sure they will) I won't be offended :)

NO.

Neither will reach that number. I doubt either will reach 80 million, especially the XB1.

Bolded: Yeah, forgot about that. 

Underlined: I was just saying in YouTube how Microsoft should start fixing their mistakes before making anything else, when Xbox fans suddenly overwhelmed me, saying that Xbox One will beat PS2. 

Because they don't need to

PS4 for sure, but XO? Damn, nope... will be lucky if will sell half of this number.

Neither will.

The generation won't last as long this time around.

From what I read about it when it occured, yep. MS made an White XBone exclusively for their employees who had been working there and were still there at launch.

edit: I just looked up an article about it, and it said that it was only for people who worked in the Interactive Entertainment division, but I know that's not true because a buddy of mine works for Microsoft as a support engineer in Charlotte, NC (Xbox/Interactive Entertainment is in Redmond, Washington) and he got a free XBone under the same promotion from the company