I do 'get it', and was attempting to explain the realities confronting your position. I was in the same situation myself, and would have originally preferred to just get FoV. With the various changes and improvements made in DKS, being required to 're-buy' the D2:ED section became much less of a problem, especially considering a relatively small price premium over what just the add-on would have been.
Practically, Larian can not get Microsoft to change their DLC policies and can not make publishers want to distribute just the add-on. At some point during development they would have realized it was going to be larger than the limit, and must have looked at what they would have needed to do to keep it under, obviously deciding, or having it decided for them, that it was not possible.
As much as you, or even Larian, may wish otherwise, if you want to play FoV on the Xbox, your only option is DKS. If you are convince the changes in the D2:ED section are not worth it, then wait for the price to drop, or don't buy it at all.
