I find it interesting seeing the yearly cycles on the graph. The Wii launched in November and the Switch in March, so there's an offset in the upticks on the graph. 46 months after release the Switch just passed the end of years sales period, while the Wii will only be getting into it. So the comparison of sales is a little problematic.
It seems from this like launching early in the year is a good way to get a little more sales in the long run. Launches tend to be limited by supply anyway, so releasing during the holiday season doesn't really provide more sales. Better launch early, then by the time the holidays hit production has settled and the total sales over the first year are higher.