We actually found that imposing a backroom dress code (in administration), increased moral and productivity.
Many other companies, particularly in IT (which I'm guessing isn't your field) have found just the opposite; particularly with regard to their tech folks.
I've never worked for a growing, dynamic, expanding company that has ever had a dress code more extensive than "wear clothes".
Not to mention in other 'backroom' departments (such as parts and service), dress codes are incredibly important in terms of safety and liability.
You seem to be fond of red herrings and non-sequitors. No one has ever denied the potential importance of a dress code prefaced on
necessity (coveralls, hard-hats, no loose clothing, etc.). The reasons for these dress codes are highly relevant to job performance, and I don't know why you keep dragging in these non-issues.
I have had dress codes on several jobs. One of those was a tech job where I had to crawl around a lot, haul around a lot of computer hardware, and so on. The dress code was limited to safety concerns, and I didn't have a problem with it since it was more or less common sense.
Other jobs I've had a "business casual" dress code for a job that entailed me doing nothing more than sitting at a computer in a dark room for 8-9 hours a day. That one was completely pointless; and the company was rife with other mind-meltingly stupid regulations as well. AAMOF, it got so bad at one point that not only was there an employee rebellion over some of their more egregiously nonsensical policies; but even middle-management rebelled as well, and that one was, fortunately, dropped. It was also one of the worst places I've ever worked, and they treated their employees like crap. The fact that they were, and still are, sliding down toward bankruptcy is no coincidence. There were massive layoffs, which disguised the losses for a while; but their stock has continued to slide and still remains in the toilet. It didn't help that the CEO was a hardcore Scientologist.
A friend worked at a company that was bought out during the dotcom era, because they were a valuable property; profitable and competitive, with a huge customer base in an area the parent company wanted to expand into. They went from very casual and highly profitable. The parent then began to make it more corporate, imposing a lot of ridiculous rules and regulations, including a dress code (almost none of their empoyees ever dealt with the public). Most of their best and brightest left, with a few die-hards sticking around. Within a year, both my friend's employer and the parent company were on the verge of bankruptcy, and sold out to a larger corp at a significant discount (the parent decided that there wasn't enough worth salvaging, and gutted it, retaining only the infrastructure and losing a good chunk of the customerbase).
The most ridiculous one was a small lab environment where we were expected to dress "business casual". After watching my manager have several expensive shirts ruined by the various lab processes, I pretty much said screw that. Being that they were a small business who were having problems hiring and retaining employees, and I was one of the best people they'd had, I got away with it pretty easily.