Firstly, I think Terrans can counter Carriers, unless of course the terran player 'not paying attention' for some odd reason.
Secondly, 'good' Terran players can kill carriers with mass goliaths just as 'good' Protoss players can kill vice versa. I've seen both ways, even when good micromanagement is done. Goliath and Carriers both have attack range 8...
Thirdly, 'godly micro' is not as hard as it sounds... for lockdown (in case terran player got it for nuking, or locking down other units, but didn't know about carriers, which happens) just select all the ghosts, if you see the carriers that's good, if not, find them and scan. During this small moment, with your left ring, press L for lockdown. Target, hold shift, click on a ghost so that only 11 are selected. Release, L, another target. Repeat.. If the ghosts are far away, and the scan goes away, the ghosts will still lock them down simultaneously...(Hope you understood this)
Phoenix, no offense but, I think you're underestimating goliaths, I mean they have the same range as carriers, have fast cool attack rate(imo), and can be massed quickly(assuming terran player is good). When goliaths are battling carriers, terran player can make more reinforcements while attacking protoss base using his left over tanks (more than 10). And by massing goliaths, I do not mean 8... lol... more like 16+ when first fighting, plus reinforcements later... goliaths take roughly 1/3 time to be built than a carrier, and is much cheaper... over accumulated time, over 30 goliaths can be made while carriers may be killing the first wave of goliaths, but are taking damage at the same time...
As for 'theorycraft' I've seen replays where all these were done... but both players were really good... perhaps you aren't playing the right people...? or haven't found a good enough terran player who can counter carriers microed by a good player yet...? Probably not me though(yet.......) And by using the term 'theorycraft' I think you're discouraging people from experimenting or trying these counter/ideas... lol
I do, however, support your notion that SVs are practially useless against carriers, since 150 shield isnt' that much of a big deal anyway...
If you have some replays to support your ideas, I would love to watch them... especially replays with you included...
I know this is zerg counter...but i have no idea... i think multiple dark swarm is a good idea, with hydras... since both defilers (with consume) and hydras are cheap...
I am sorry if I've went off on a tangent here people...lol