Why Most Business Case Studies Fail

I know a thing or six about writing effective case studies. I have asked for and written detailed case studies for all but one of my books. All told, I've probably penned 50 or so case studies over the years.
When I peruse the websites of most startups and established software vendors and service companies, I'm astonished at what I see. My observations typically fall into two buckets:
- Those that lack proper case studies
- Those with case studies that suck
Rarely have I ever seen an effective three- to four-page representation of how a company's wares helped one of its clients. When was the last time that you read a well-written case study by a software vendor or consultancy? I'm guessing that it's been a while, if ever.
Why Case Studies Matter
It'll only take a moment.