What do you mean by, "we're not allowed to set prices"?

Isn't that precisely what an independent contractor does, sets their own prices on a per job basis? I've gotten quotes for concrete work that varied by as much as 2x ; there is no uniform pricing

I've always looked at this problem as one of scaling. Americans are so used to having things clearly priced and on a shelf because of the efficiency of inherent in the big box stores, chains, etc... When they encounter something that's not that, they kind of freak out because a) they have to negotiate with an actual person and b) it's going to be more expensive.

And independent construction contractors are like the least efficient operations I can imagine, it's just not scalable.

My office is next door to a general contractor and I've nosily observed how they operate over the last couple of years. I had them quote a bathroom addition for us. Their quote was breathtaking and it occurred to me that the owner of the company had advanced to the point that he thought his job was sales and management, not doing actual building work, so he's trying to price in a $60-75k salary for himself into all of his work.