Anyone is free to ignore my words or let them stick. If you choose to dislike them, there must be a reason, as well as if you like them. I did not say, we get each and every job with this policy. Not everything is as black & white as you put it. If some guy/gal comes in with a truck and want words on it, along with a picture of a flower and it only takes 15 minutes to arrange words, that is part of my job........ no charge, but if they don't give a deposit, they don't take any drawings with them. They must commit it to memory if they go elsewhere. Again, that to me does not represent artwork arranging words on a truck or electric sign. Any truck or nice sign needs very little time to turn out just right. If you know your job/capabilities...... certain things just take place automatically. If you know going in this or that will take you X amount of time, add it to your cost in fabrication/production somewhere. Now, if that same person wants you to make mock up after mock up and can't visualize a blessed thing, they are warned up front of the art costs. You can tell these people within 2 minutes. That high cost makes them decide quickly and not waste your time.
So, it has nothing to do with being an established or some niche shop. It has to do with company policy and working within the rules. You can also choose to ignore your own rules, if you want. But at least they are posted and you have no surprise costs going in and your potential client understands it. The OP wanted to know if he could get hidden money for his drawings. My answer is still..... NO, not if you never told them. With some of your ideas, do you go back later, if you never told them a thing about ownership rights/costs and try to extort money from your free drawings ??
Heck, I just did a sign for free the other day. It was actually a name addition. Took me less than 5 minutes to do. She came back and I told her no charge. Why, I was prepared to pay you ?? I realize that, but our shop minimum is $125. I can't charge you that for what we just did, so rather than put it on the books, I'll get ya next time around. She said, alright. This sign was for my mother, but where I work, we need to order a lot of signs real soon and I'm the person in charge of that kinda thing. I'll be back next week. Turned out it was for 65pcs 2' × 3' reflective aluminum signs. Gave her a price and she said, not a problem.
It does pay to do freebie stuff, but it helps to know when, where and why. I got lucky on that one, but the same scenario has happened many times over the years.