It's really getting annoying seeing people doom the Xbox One. Dont make the same mistake I did. Xbox One has billions of dollars backing it. It WILL sell well. Look at the Toyota Prius. People in the auto press were calling it a joke when it was first released and laughed more when Toyota started selling each Prius at a loss. Now look at today, Toyota is printing cash with the Prius and no other car company comes even close to it when it comes to hybrid sales.
I'm not a Xbox fan but I wont bury my head in the sand and underestimate a company that can do MAJOR damage with the Scrooge McDuck cash they have. Microsoft has made me eat too much crow. LOL.
See the problem with your examples is that your comparing the One to successes outside of MS, frequently ignoring all of the variables that play out here. Zune was also backed by Microsoft, I don't know what its doing now but it sure isn't printing cash.
There is a limit, a cost benefit ratio. I honestly don't understand how anyone can get hyped up on how much money MS has and can "virtually" spend on the XB1, because its barely anything has changed since the 1st XB released. Obviously, there is a limit on how much they can "actually" spend, the effect of money spent is asymtotic not exponential.
It doesn't matter how much money MS has, if XB1 doesn't hit key points this holidays, then it won't get up to par with the PS4, the last region where Xbox would have a chance.
But that is only with regards to the scope of the PS4 as a competitor.
In relation to itself as the OP suggests, once again the effect of money spent is asymptotic, not linear or exponential. Diminishing returns in other words. When a billion dollars has the effect of only a million dollars, even MS is forced to reconsider. After all, MS didn't get rich by dumping money into non-core products.