I like your reasoning. Here's another couple of relevant questions to consider, to which I haven't the foggiest clue of the correct answer.
Did the sauropods commonly held to be prey for T-rex & other large predators travel in herds?
Were they hunted by lone T-rex assailants, or by packs?
When a sauropod was brought down, how much meat was left over for scavengers to pick over? Just possibly--I don't know, nor am I even confident in my guess--a lone T-rex might gorge and leave XYZ tons of meat on the bones. OTOH, a pack/herd/pod/gaggle/wtf of velociraptors, or several packs, might successively pick the bones clean shortly after the kill. That brings to mind another question.
Do we know the "pecking order" for scavengers following the kill of one of the sauropods?
If you had the occasional XYZ tons of meat lying around in heaps, and T-rex was a scavenger, but near the top of the pecking order, then I guess getting the requisite protein wouldn't be as much of a challenge.
If there are any true paleo's around here, though, they should be able to tell me in a matter of microseconds just how bad of a rectocranial inversion I have, even to have asked those questions.
I defer to their judgement...
Cheers!
There were no late Cretaceous sauropods in North America until the very end of the dinosaur age, when some titanosaurids moved north across the land bridge from South America...evidence indicates that Hadrosaurs and Ceratopians were the primary large herbivores in TRex's environment....to my knowledge no group burial of TRexes has yet been found that would provide evidence they lived in family groups (unlike the Giganotosaurs of South America, for which 2 mass burials have been unearthed, most likely courtesy of flash floods that drowned them)....