The USA way of doing things
It is the USA way of doing things.
The design philosophy is: "You make the smartest super-duper ultra-guided fire and forget shell/missile/bullet".
If you compare this to what Russians, Israeli, even French do - they use multiple relatively dumb multiple pursuers and some intelligence in the fire control on where to place the pursuers initially. Instead of really hairy engineering and 1M lines of code for a single ultra-intelligent shell, you use a few pages of really hairy math and some algos to solve numerically particularly nasty differential equations. High up-front cost, very low cost of the actual weapons themselves.
If you compare both mathematically, you get significantly higher kill probability with the second approach at a fraction of the cost. It is trivial to prove too - various proofs both from game theory and from optimal control exist for that going about 30 years back.
If we apply game theory to the "meeting of minds"... Err... I am not sure I like the results. In fact I seriously dislike the results, because the second approach is likely to win every time. Time to tell the yanks to keep their stuff to themselves and buy some weapons from Israel, Turkey, Germany, Sweden or somewhere else (*).
(*)UK is missing in that list because BAE is so engrossed in fitting into the American weapons design gestalt that it is by all means an American company. It talks like a USA arms supplier, it thinks like a USA arms supplier, it is in fact a USA arms supplier - nothing British about it at design level.