You know why, COST plain and simple.
Not everyone buys a Rolls Royce, not everyone shops at Neman Marcus, not everyone uses Snap on tools.
You mentioned you work some retail, that is what I have been doing for the past 12 years and my impression is this. The large chains would gladly have us wire the building with zip cord as long as the inspectors say OK and the doors open on the day scheduled.
I was all set to do a small remodel with an electrical contract of about $180,000. Another EC came in at $150,000, the GC still wanted us as we had a good reputation and experience. The retail customer stepped in and said use the cheaper EC. So the cheaper EC got the job and screwed up a lot of it, we where paid T&M to fix it and the customer still was ahead money wise. They don't care that behind the walls and above the ceiling it looks like a train wreak.
For most customers all that matters is the lights are on, the details of how that happens do not matter.