Well, they went down in March and are now back at Jan/Feb levels. That hole in March could be systems diverted to Europe (as ioi's new graph doesn't include Europe yet), or the higher Jan/Feb level could have been some overflow from the 800k extra systems that Reggie had ordered for Christmas but mysteriously never arrived in America. I still wonder what actually happened back then, but we'll never know.
Hardcore gaming is a bubble economy blown up by Microsoft's $7 $6 billion losses.