How can the consumers quantitatively evaluate? By subtracting the costs of the extras from the total price tag.that is the backwards part...
subtract the cost of the total price tag from the sum of their parts, which is how you know how much money you are saving...
itemizing the savings per item is pointless as you only save on the total package, and you would have to also know first what the saving value is by doing what I said first.
Total cost - bundle cost = savings
you do not need to go back and then subtract the savings from the bundle cost to say you are only paying x for this or that, that is useless data.
If I buy a chromecast and it's bundled with $20 google play credit for the same price, that does not mean i'm getting the chromecast for $20 off...
If one bundle I attribute the value of the xbox (using your logic) to ~$299, and another bundle where (using your same logic) the value of the Xbox is $399 which one has better value?
Spoiler for Hidden: