PS5 isnt comeing until november 2020 imo, thats like ~19 months of sales (after the 95m-98m mark).
According to VGC-numbers, I looked to the peak-year (calendar-year) for sales.
PSP peaked 2008, Vita released 2011.
DS peaked 2008, 3DS released 2011.
PS3 peaked 2011, PS4 released 2013.
X360 peaked 2011, Xbox One released 2013.
Wii peaked 2008, WiiU released 2012.
WiiU peaked 2014, Switch released 2017.
So, with the exception of the transition Wii-WiiU (and Wii had an unusual life-cycle), the successor followed 2-3 years after the peak year. Remember also that 3DS and Switch came early in their respective year, not late. That leaves only the transition from PSP to Vita at a full 3 year-window.
Now the shipments for PS4 peaked already in the financial year 2016 according to Sony, sales peaked in 2017 (calendar-year) according to VGC. We know now 2017 is the peak year in sales, as Sony projects much lower shipments for the next financial year. So while November 2020 is still supported by the data, it is actually the latest possible date according to earlier transitions. The data suggest more that the successor follows after two years, but a bit longer (WiiU->Switch, DS->3DS) is possible. So yes, I'm a bit sceptic to the November 2020 date.
Anyways, my prediction for 100M-110M is probably also off. I thought about it, and with this projection PS4 is at 95M in April 2019 and the next financial year should be around 10M, so 105M. The last 5M should be possible. So with some more thought into this, I think the 110M-120M window is more realistic.