I do think PS4 will outsell the Switch lifetime because the hardware, for one, didn't age quite as fast as the Switch (which will hopefully offer a mid-gen upgrade like the other two).
Mainly, though, it's because they probably had the least competition for a huge portion of their run than any console since the first few years of the Atari VCS in NA. I really can't think of an example where a console had only two competitors, and both competitors absolutely face-planted and botched their entries from the start.
The end result was that the PS4 was simultaneously affordable and the strongest hardware-wise (that almost never happens), not held down by expensive peripherals, was the best system for multiplats, had a strong first party lineup, and was really just the logical choice for almost everyone.
We might not see such a favorable climate for a console to sell well again going forward. I don't think the Switch can ever catch that even if it does sell extremely well.







