So are most Xbox SKUs just not being sold new on Amazon anymore or is Xbox just that much less popular on Amazon? Because you'd otherwise expect Xbox and PS4 to do about even in the US, with PS4 slightly ahead.

Just not that popular. Last month was the first month it didn't show up in the Top 100 for the month, save 3 months right after the Switch's launch. It seems to be making it up at brick and mortar stores, though, as it was less than 35K away from the PS4. Of course, it is still being sold $50+ cheaper than the PS4. It will be interesting to see what happens when the PS4 finally gets its next permanent price cut.

And Mario Kart Wii enters the charts again. Seriously, when will that title run out of gas?

As low as sales already are in recent charts, I'd say a $50 price cut for PS4 might push XBO down to 3DS levels.

KH3 ends April on a good note. The highest ranking at 16 in Italy. It didn't chart in Au and Spain, but 1.5+2.5 is at 62 in Spain. Good day.

No May chart?