You really should compare the launches by region - otherwise you include extra time in one region, too little in another and so on.
That PS4 had a strong launch isn't surprising - as brands become more established year one fans become more and more dedicated. I've always worked on the assumption that the 9m people who bought PS3 with no games for $600 are the people buying PS4 now.
NES hardly sold at all initially, same with PS1. PS2 and SNES had very strong launches. PS3 and N64 had strong launch years relative to their lifetime figures 9m out of 90m, and 6m out of 33m. The PS4 arch will be more concentrated in the early years, just as PS2 and PS3 were concentrated than their predecessors. The only difference is that PS3 effectively had no peak year - it sold the same amount give or take 10% for three years in 09'-11' which is uncommon. PS2 and PS1 were voliatle and had definite peaks 20% higher than the others.
People are difficult to govern because they have too much knowledge.
When there are more laws, there are more criminals.
- Lao Tzu
