As scientific as that survey may have been, I believe more than 30% of sign shops give design away.
We only do layout and design of signs and business collateral. We work directly with corporate clients and we have sign shops we freelance for. Either way, we have to get paid. But currently, all our sign shop clients do not charge the client, they write it off as the cost of doing business and add that time equally to all the clients or when they land the job.
I have worked for quite a few sign shops and none of them charged outright for layout or design. They all believed it was part of doing business.
How do we stay in business when most clients are not willing to pay for sign layout and design and most sign shops are not charging? By being a little more accurate and creative, designing sign projects that the average sign shop can't handle, and allow the client to take projects out to competitive bid. Many times a face change turns into a complete branding overhaul... the 1000 dollar budgets we sometimes work with will turn until 30k. We also rarely design just an apartment sign, it's usually project wide. So a 5k monument sign can turn into 200k because of all the code and related signs that need to be replaced. You work with a real estate management company with 100 properties? Then you have to start to factor in where giving the design away becomes cost prohibitive. We sometimes encourage shops to charge a little for larger projects, then allow the client to bid out the job, but we design to the shops specialty. That way when bids come back, the contracted sign shop has a better chance of being awarded the job and it also build trust with larger corporate clients.
You mention the creative brief. We don't use it for tire kickers, we use it to keep clients on track, define the scope of work and incorporate that into the contract. Without a creative brief, we have no direction, without a direction, the client will use up valuable time having us design without any real goal or target. When we design something to the design brief, and the client wants to go a different direction, we get to charge more because the scope of work has changed and of course, they have to fill out another design brief.