I agree. AA/BA can't even work well together - neither are able to print boarding passes for the other - and not only are they founding members of OW, they are in a JBA as well.
Last month OKC/LHR and return - both ends couldn't print a working boarding pass for the other.
AA can't seem to figure out that if they are going to route a large portion of atlantic traffic on BA, they need to work something out for lounge access in LHR T5.
It took me years, but when you step back and look at it, it's really a sad picture. Glad to not be playing along in 2017 anymore.