Ah, you count financial years, I looked at calendar years and ignored the launch if it happened in November or December. 2014 has WiiU more than 2013. But whatever, either way peaking in the first year is the exception, not the rule.
Ok, I should have specified the demarcation of my years (done in bold). It's the same thing when we compare consoles sales with launch aligned.
Yes it's an exception, but this exception already applied on 2 devices of 8th gen. I will wait until March 2019 to see if the Switch is also a victim of this exception (but with a larger sales volume). This may seem implausible, but nevertheless not impossible.