But non-US programs come with other tradeoffs. Usually no complimentary upgrades and no access to VIP phone lines. Yeah, you get lounge access on domestic itineraries but as you're talking credit cards, those cards can potentially open up lounges as well (Priority Pass, Amex Centurion lounges etc.)
IMO, the use of credit cards and the choice of program within a given alliance doesn't really resolve the OP's conundrum. (Which involves travel being split up across three alliances.)