I believe the difference is that in this case, RS is being used as an erasure code (which means, you either have the data or you don't; the drive has either failed or it hasn't). Failures are (approximately) uncorrelated (assuming different parts are stored on different hosts), so for this use case, RS approaches optimal in terms of storage used (some metadata needs to be stored, which is overhead).

Not for this use case, no.

Turbocodes are more CPU heavy as well (also require FP math or some workarounds)

For just detecting and correcting bit errors in blocks of data, RS is fine. Now if you're getting data from the other side of the solar system Turbocodes are worth it.

For short block lengths, R-S codes and turbo codes have similar performance (but turbo codes are harder to design). I think the patents on turbo codes have expired.