The point of TQM, or Deming, is not to focus on failure or success, in fact, but on process. The process is supposed to account for all the details.
The reason the Space Shuttle didn't fall apart at every single joint was due to engineering and construction process-based quality control. This is the same, but extended to business.
The point is to fixate on the process, not the success or failure, and not to do it piecemeal. Implement process at all levels.
Another example: the reason Japanese cars are such high quality (especially when compared to US manufacturers a few decades ago) is not due to just parts or engineering, but also fundamentally management style. Few US CEOs would reach this conclusion. This was Deming's fundamental point: the workforce is part of the process; every part is important to the end result.
"Asking for details about this is like asking what type of screws were used on the Space Shuttle and claiming that's why it actually got to space."
One interesting interpretation is if you focus on failure, you'll focus on how the shuttle failed to get into space one time because the elastomer in a solid booster joint was required for political reasons because the segments needed to be shippable, and the specific elastomer had acceptable to excellent high temperature performance but epic failure at cool outside temperatures.
So if you fixate on failure, the way you "fix" Walmart, or America in general, is by copying one or a couple small details, like the painting scheme at Costco or the peculiarities of their payroll system or something. If on the other hand you fixate on success, then an analysis looks a heck of a lot like your post, more or less.
Or more generally, you fail because of details, but you succeed because of bigger issues, like using TQM Deming or other paradigms.
Flailing about for better numbers works in a sea of incompetence, but usually doesn't work if your competitors actually know what they're doing...