I wouldn't call it boasting..... back in the PS2 days when sony openly said their sales decimated that of the cmpetition? Now thats boasting.

This is just then disclosing sales numbers. Nintendo will do the same, only people not doing it is MS, which is a far cry from what they used to do with the 360.

Fighting with eth XB1X?

No..... as far as MS is concerned right now, its not a fight anymore. They are just trying to remain healthy

While I agree that it won't reach PS2 numbers. It doesn't really need to. 120-130 is more than realistic for the PS4. 
As far as the argument with the Xbox One and Switch go. 

The Xbox One X is no threat whatsoever to Sony. Power isn't everything and it's not nearly as big of a deal as people claim it is, if it was, everyone or the vast majority of the gaming audience, both casual and dedicated, would have a gaming PC and most of the profits and revenues for gaming would come from that.
And that $500 price tag was a shot in the foot, just like it was when the Xbox One launched in 2013 against a $400 PS4, and now a $400 PS4 Pro that could very likely drop to $350 in the near future. 
Right now, Microsoft's Xbox division is just trying to stay alive and make the most out of the situation they put themselves in and hope to start fresh with their next system.

As for the Switch. 
I do believe that the Switch will ultimately be the one that dethrones the PS4, the signs are already there. This is the PS4's peak year thus far, and yet, it's been going back and forth with the Switch, which just launched and still has a rather limited library, especially compared to the PS4 right now. And as soon as Pokemon drops, that'll be all she wrote for the PS4's reign on top.
The Switch's time will come, but not now. 

And I especially disagree with the point that there's less of a reason to buy a PS4 than before.
It has garnered an incredible library, with plenty still to come. There's a reason most people on this thread believe 2018 will be the peak year. 
Add that to the fact that they can still do various price drops, the PS4 has plenty of juice left and there are more than plenty of reasons to buy a PS4 now and later in the future. 

I still don't think anything it will hit above 113 mil.

But then again, didn't Sony sell millions of PS1's and PS2's after they were already replaced? Or am I wrong about that?

PS1 sold over 30 million after PS2 was released, and PS2 sold over 40 million after PS3 was released. Curiously, though, PS3 won't even reach 10 million after PS4 was released.

Yeah, I heard something crazy like that. So does that mean the only reason the PS1 beat the 64 by so much is because of their longterm sales? Or was the 64 still up on the market? That's ... crazy sales!

I kind of have a feeling the days of that happening are over, though. Which is why I strongly believe in the 108-113 mil PS4 sales prediction I have. 108 might be lowballing it though, depends on next year sales really.

Well, I definitely wouldn't say that. PS1 was still comfortably in the lead before PS2 came out. As of March 31st, 2000 (right after PS2's launch), PS1 had shipped 73 million and N64 had shipped 31 million. PS1's lead was certainly smaller, but it was still ahead of N64 by 135%. Just not the 200% that lifetime figures indicate.

Anyway, I do agree that selling so many units after being replaced is probably out of reach nowadays, though I still think PS4 can reach 120 million.

Yeah I guess "so much" was a tad hyperbolic but ya know what I mean. That's certianly still a lot, more than 2 times the N64. 

The PS4 probably could. It's all speculation honestly. 130 mil wouldn't be toooooo surprising but I think anything more than that is unrealistic. One thing that helps the PS4 is it's continued focus on 1uping itself every year. As critical as i've been of PS4, it's first 2-3 years missing big Sony IP(aside from a few series) really alowed them to ride out first year sales, only to get a second wind with the console. God of War, spiderman, days gone, and Detroit are all going to kill it. If next year is better than this year, I think 115 mil will be even more likely. Now how will it's 6th year fair? That's the question.

It will be very interesting to see how things play out. PS1 and PS2 had a huge advantage over PS3 in that they were both the most popular console of their generation, and they also went as low as $49.99 and $99.99, were PS3 only went to $269.99. With PS4 being the most popular again, and having every chance of reaching $99.99 - $149.99 range, it very well could sell much more in line with PS1 and PS2 after PS5 hits. 

I still think we won't see PS5 until 2021 or 2022 when the tech to make a worth while generation leap becomes possible. PS4 will be heavily supported for a solid decade, and I would expect to see Sony continue to release a few major games on PS4 even slightly into the PS5 life cycle, as it has lead to good rapport with consumers. 

Sony is in an extreamly positive position with PS4, and has many, many options with where it goes with both PS4 and PS5. I personally hope for more form factors, a premium version above the Pro, a Digital only edition at the entry level, a Laptop/Tablet, and a Portable/Phone. Build out the platform into something that can encompass a fully PlayStation lifestyle, and then launch PS5, and begin to transfer the userbase to the significantly improved next gen worthy platform. All while continuing to build a userbase with the super low cost PS4 in smaller or lower income markets, this will be where they can reach 20, 30, 40, or 50+ million people after PS5 hits major markets.

I think PS4 will be over that, before end of 2020, when PS5 launches.

and as you said, it ll keep selling after the PS5 releases, putting lifetime sales into the 120-130m.

I may be the only one who thinks that, but I still can't name more than 5 games that I would actualy play on the PS4 today. If I had to buy a PS4, I would only play to Uncharted 4 (and why not, Lost Legacy), Horizon Zero Dawn and Batman Arkham Knight. I'll wait until the release of God Of War (4?), Red Dead Redemption and Battlefront II and then the console will worth the purchase. That's where I agree with most of you saying 2018 will be the best year for the PS4.