PS4 LTD Sales should be at least 140 Millions

[Mummelmann]

"I looked at trends from past consoles and I arrived at this"

That should start the alarm clocks right away, shouldn't it? This is not how it works and it's never this simple. People did the same thing for the Wii, showing how it was tracking way above the PS2 from the start and was sure to destroy its lifetime sales record, it has also been done for the 3DS and people had insane predictions for the sales of the PS3 in its twilight years, even stating that it would catch the Wii due to the infamous ten year plan.

I don't think the PS4 will even come close to 140 million, beating the PS1 would be a feat in today's market and is a more realistic goal. "At least 140 million" is way over board at best. The 7th gen was unnaturally long; it was the exception to the rule due to HD being ushered into the industry, rising development costs that required completely reworked developer paradigms, exploding online communities and features and an unprecedented close horse between the three consoles.
Also, mobile gaming, browser and social games were much less of a factor and we had a huge, global financial crisis to deal with.
Circumstances caused the 7th gen to be really long, these are not present in the 8th gen, using the 7th gen to predict the length of the 8th gen is almost as faulty as using past console sales to predict the lifetime sales of the PS4.