PS3 got to 87m. Everything still points to PS4 selling significantly better.
PS4 had it's best first 6 months this year, in fact.

MS and Nintendo are no longer competing directly with Sony. I don't see either of them pushing Sony to rush PS5.

People seem to forget that Sonys keeps their consoles selling for ten years (and not just six to seven years). Its even sadder that the dont know this on a sales site.  It will pass...

No. It's 17.5M. Actual LTD sales at the end of 2015 were at 35.9M, while sales at the end of 2016 were at 53.4M. 53.4 - 35.9 = 17.5.

My median projections have the PS4 in the 100-110M range, probably towards the higher end, and assume a Nov. 2020 release date for the PS5. Optimistically, I think it could hit 120M, but that could depend on having very strong legs. Assuming my estimates for 2017 come true, the PS4 will be sitting at 72.4M units globally. That's a very high number to be sitting at for a system that appears to be peaking. No other system has ever sold that much before peaking. The PS3 & 360 were both over 60M when they finally passed their peaks, and that was a record, and was largely due to them having very belated peaks (fifth and sixth full year, respectively). Sony is running out of people to sell PS4s to, and sooner or later, probably sooner, the PS4 is going to be entering the terminal decline phase of its sales life. With the PS4 not having nearly the market share the PS2 did in the U.S., trailing behind the PS2 in Europe (probably due to the UK market being competitive), and the Japanese market shrinking, I don't see the PS4 selling anywhere near as well as the PS2. 150+M isn't happening.

Now, it is entirely possible that Sony could try to squeeze the PS4 for all its worth to try to extend its legs while putting off the PS5 as long as possible. The rate of tech advancement is slowing down, so Sony & MS have an incentive to extend a console generation as long as possible in order to allow the tech to advance more and make the generational leap more pronounced (I think last gen was as long as it was on purpose; imagine how weak the PS4 & XBO would have been if they were launched in 2010-11). They could keep going for deep sub-$199 discounts into 2019 and beyond, which could get them a good bit above 120M, maybe even reaching 130M. But at some point in a system's life, no amount of price cutting will help improve sales. Eventually, they just run out of people who are willing to buy a current-gen system.