Sulphate Attack on Foundation Footer

I came across this situation recently and am wondering if any of my readers, inspectors, engineers, or otherwise, have seen this as well.

The inspection was a 1970's ranch home, brick veneer exterior siding with vertical and diagnoal cracking.  Upon entering the crawlspace, I thought there might be an efflorescence issue.  After closer evaluation, it became apparent there was something much more serious going on than just efflorescence.  A structural engineer on site for this inspection commented the condition appeared to be a "sulphate attack".  The attack appeared to be more specific to the foundation footer than the foundation wall.

Why was this happening?  My research indicates a chemical reaction "involving sulphate, that when present in contaminated hardcore along with a source of moisture, reacts with cement present in the concrete causing it to expand and contract (and deteriorate)."  This condition can take from 10 to 20 years to develop. (source: Laboratorytalk Magazine)  This particular home did show signs of negative grading at the exterior and gutters full of debris.  So at the very least, these exterior defects were contributing to the presence of water in the crawlspace.  Over time, the combination of water runoff and the chemical reaction between soil and concrete has left any potential buyer with a tough decision to make: buy or walk?

Has anyone else run across anything like this?  Do you agree with the structural engineer's assessment?