In simple scenarios with two actors perhaps, but I don't think that holds true for complex scenarios with multiple participants. Somebody who steals the best from everybody and is always one generation behind the state of the art in every regard may still prevail against all others because they are a Jack of all trades, master of none.

I'm not saying there isn't use for knowing your adversary's capabilities (especially in designing your own offense/defensive systems) but very little of that knowledge informs the core of future arms programs.

..unless you are China