S.G. obviously has no practical knowledge of the inner workings of hard drives. I'm only an observer, but I at least understand that headstack replacement is the solution in 99% of cases where there is difficulty in reading the data (aside from media damage or SA corruption). Sadly, he is trying to extrapolate what he learned 30 years ago to the present day.
Steve, those old heads were based on a single coil that was responsible for both reading and writing. They were soon replaced by magnetoresistive (MR) heads. These contain separate read and write elements. The failure mode of MR heads is completely different, as I explained to you in a thread which one of your stooges subsequently deleted.