That view was mostly abandoned in the 70s-90s. They were just built very lightly, using a lot of the same weight-saving techniques (hollow, airy bones) used by modern birds.
(This lightness makes it unlikely they could function well in water; their torsos would float before getting very well immersed, which would indeed take weight off, but would also mean they'd have to hop along awkwardly on their front feet. This is supported by front-feet-only sauropod prints on once-submerged areas.)
Side note: I'm very interested to know if those weight-saving measures came from a common ancestor between sauropods and birds, or if that's just convergent evolution in two branches of the dinosaur family that were solving similar engineering problems.
(This lightness makes it unlikely they could function well in water; their torsos would float before getting very well immersed, which would indeed take weight off, but would also mean they'd have to hop along awkwardly on their front feet. This is supported by front-feet-only sauropod prints on once-submerged areas.)