im almost positive the first numerous months of the ps3 were supply constrained, and even longer for the 360. I very well could be wrong though, and even if they werent they were both being hugely outsold by the wii, which this comparison seems to ignore.
360 was supply constrained until April 2006. PS3 was supply constrained until right after Christmas 2006. Wii was supply constrained until sometime in early 2009, if I recall correctly. All U.S., of course.
I can understand reluctance to drop Xbox One price with a true cut, but it still baffles me that the 360 is still so expensive. It could definitely use a big price cut for the holiday's, seems way overdue.