The "all in one" aspect which Microsoft advertise is for the fact that it can do more than just video gaming. It can watch Bluray movie, watch TV show, listen to Xbox music, has HDMI input for DVR. etc. Hence "One device for all entertainment need".It's disappointing that Xbox One defies itself with the "all-in-one" due to being unable to have backwards compatibility with 360 and/or OX games. It's not like it used the expensive CEL thing like Sony had on PS3.
If anything, Wii U is the only one in 8th gen that doesn't expand beyond video gaming.
X360 uses Xenon chip, which is custom made PPC chip with Microsoft being the only customer. When you have only one customer for a custom chip the average production cost is high. Microsoft had to resort keeping the chip in-order-execution (as opposed to out-of-order-execution) to keep chip cost down. Nintendo suffered the same fate with Gekko, Broadway, and Espresso, being the only customer that orders Power 7 based CPU.