I'm no meat expert but I thought about 3 weeks postmortem is when it (beef) gets it's best natural tenderization. Maybe somebody letting it rest longer trims off some of the microbial growth before prep and cook?
I once found about half of a McRib sammich under my car seat. I believe it had been there "dry" aging for about 45 days. After warming it up in the sun on my dashboard for the rest of the afternoon it was better than ever!