Just because it's not been used for a while does not render it obsolete. There's always a chance where plinking away with BVR rockets won't be possible/acceptable...
The strategists determine whats obsolete, rightly or wrongly. Hence they accept the responsability of loosing assests in the hypothetical situation of getting into one.
Another words they determine the trade offs are worth the 1 in what ever chance of that occuring, versus advantages of what ever else they think is important.
Or more likely redefine as important as the true capabilitys of the new platform become apparent.
