6 million aligned lead over PS4... maybe, just maybe Switch will win this one after all.
I hope that's sarcasm and self-depreciating humor at this point.
Switch is 6m ahead with one holiday season less. As always, 12 month intervalls of comparison work best for consoles that didn't launch anywhere close to in the same month.
12 months - Switch ahead by 2m
24 months - cumulative Switch lead hits 4m
36 months - cumulative Switch lead reaches 6m
48 months - cumulative Switch lead is 13m+ (projected)
Year 5 and 6 for the PS4 are ~19m and ~14m, respectively. Would be a major upset if Switch didn't continue the trend of growing its lead over the PS4 every year.
There's a good chance that Switch's life to date sales by month 72 already exceed the PS4's lifetime sales.