The big test of that enduring popularity will come with the launch of their next Xbox this year, if that does well and closes the gap with Sony then MS will stick by Xbox along with it’s grander plans for Xbox in other areas like PC/mobile.

If it doesn’t then your right it’s time to let it go, Amazon would be the ideal buyer as they both cover a lot of the same ground, plus it has the resources and tech to fill in the gaps.

Samsung would desire it having a platform finally to call their own with some history as Samsung has been a long time promoter of Xbox for selling their TV’s, but users would be wary Samsung could handle the business right.

Any Chinese entity buying Xbox would be a straight up death sentence, the territories were Xbox is popular are deeply suspicious of Chinese companies and the gamer audience in particular is as well. Xbox might become popular in China but thats the only place it will ever be.