Probably because
(a) the prime concern relates to maintaining energy for the approach .. ie to cover the consideration of an airspeed reduction. One needs to note that the maximum energy is a concern for runway overrun also so there has to be both upper and lower speed limits in the energy management plan
(b) crosswind doesn't have a great effect on the approach energy .. rather it is a challenge to handling management
I presume that the various heavy OEMs will have internal papers relating to their strategies .. can't say that I have ever seen anything definitive. There may well be an article in one of the Boeing Aero magazines.