Industrial uniform

I recently attended a technical fayre and mini exhibition. As i walked around it was obvious who the business people were -they were the ones wearing suits. Technical types (such as me) and academics  rarely wear suits. So why do so many others ? The suit is a business uniform. The abence of a suit is also a kind of uniform. It is a kind of statement that says 'I'm more interested in the science than the business'  and that actually is the case. There is nothing wrong with that. You need people who are focussed on the science just as much as you need people who are focussed on the business, in order to provide a proper balance. But the odd thing is this; the suit is a visible credential , its almost as if in business you wouldn't trust someone who wasn't wearing a suit. And yet I distrust people more if they are wearing a suit.
Recently in hospital whilst looking after my injured child, I visited a cafe to get a drink. In the cafe was a person wearing a pinstripe suit and waistcoat. It was obvious they were in the hospital to sell stuff. It felt really inappropriate that someone was there is full view with the purpose of making a profit whilst the rest of us were only concerned about our sick children. I know that is irrational because everything that is used in the hospital results in profit for someone, and there is so much waste that selling to hospitals must be very profitable. But it just seemed a bit too in your face. Do business people feel they have a better chance of a sale if they are in a suit? Do they think that it is being disrespectful to the purchaser if they dont wear a suit? Do they think the customer wont buy from them without the suit?
In my company none of the technical people wear suits. Most of the commercial people do however. Even those that rarely leave the office or meet people outside of the company. Perhaps they are trying to instill into their colleagues the impression that they are  a professional, perhaps they are trying to instill into themselves the very same opinion. 
I think that in the technical community at least there is the opinion that the way I look does not affect the way I think. Obviously I have a lot of sympathy with point of view, but I also think that if the way you dress makes you feel more confident it will show through in what you do and how you interact. Equally so if wearing a suit makes you feel uncomfortable.