I thought I was being optimistic when I thought Spiderman would do great to finish around 6 million and here it looks to have probably doubled that.

And PS4 is closing in on 100 million units. Good performance and rebound from the struggles of the PS3.

Spidey numbers include digital?

congratz to insomniac

we probably will only get "shipped" numbers from Nintendo

as Sony has all the data on that I'll go with a confident "yes"

Very interesting. I always like to make projections, so for December 2018 NPD we might get something like this:

2014: 4.1m NOV NPD 831k, DEC NPD 1.065m DEC NPD %= 26%

2015: 5.7m NOV 1.539m DEC 1.582m DEC NPD %= 27.8%

2016: 6.2m NOV 1.1m DEC 1.568 DEC NPD %=  25.3%

2017: 5.9m NOV 1.582m DEC 1.080m DEC NPD %= 18.3%

2018: 5.6m NOV 1.478m DEC????????

Assuming 18% and PS4 is above 1m. The potential but extremely unlikely of 28% is above 1.5m. Ratios have been dropping and might have dropped further, so a 15% would be 840k. All in all, it probably didn't do too terribly.

2019: 15.5 million
2020: 13 million

Bonus:
2021: 7 million
2022: 4 million
2023: 1.5 million
2024: 0.7 million - Discontinuation
2025: 0.14 million - Final Year on market

Final LTD sales for the PlayStation 4: 134.44 million units - Making it the 3rd best selling system of all time. (Albeit a distant 3rd behind the DS and PS2.)

For the bonus, Is that similar to how PS3 sold after the PS4 came to market?

Also, what do you think Switch will end at? Asking cause your response is so detailed. 

Veeery much doubt that.

1. I don't think the PS4 will drop that much in price outside of promotions. 50$ each is way more probable

2. PS4 doesn't have the same lineup of great games and recognizable IP this time around. It's not bad, but can't compete with last year's MHW, GoW or Spiderman, to just name a few.

3. Switch not doing any pricecut while in their third year would be pretty much unheard of. I don't expect very much to be fair (299$ with a game included, 269$ becoming a new base model plus a 299$ Model with bigger internal memory (64GiB or 128GiB, depending on how fast Flash Memory gets cheaper) but no game or just a Free to Start with maybe some store credits and/or unique items/skins preinstalled. That's not very much of a pricedrop, but hey, it's something.

4. 17M are a lot. PS4 made 18M this year, and that's 2M less despite it's stellar game releases this year. I said I expected 13-15M in another thread and I'm willing to extend that maybe to 16M, but that's really maximum, even with TLOU II. Market really starts to get saturated, I'm sure sales will drop off quite a bit in the following months compared to last year.

that's what I call, heavy sales.

Kind of, although the PS3 was obviously selling on a lower scale. About half my projected guesses for the PS4. As a result, it only had 4 more full years on the market after the PS4 launched as opposed to the 5 years I'm giving the PS4 after the PS5 launches.
The PS3 sold these amount of units in the 4 years it had left after the PS4 launched:
2014: ~3.56 million
2015: ~1.34 million
2016: ~0.52 million
2017: ~0.11 million

As for the Switch, I can't really give an exact estimate because we are still in its early life cycle. I think it will definitely, without quesiton, pass the 3DS, PSP, GBA, 360, and if Nintendo doesn't make any blunders, it should also pass the Wii and PS1. Afterwards, depending on how well it sells after 2019 and how good its legs are, it may even reach the OG Game Boy/GB Color. So for now, I'll give it a rough guess/estimate of 105-120 million.