What if "promotion" doesn't necessarily mean domain over other people, which seems to be the other issue. There can only be one SVP of Technology, for example, in most organizations.
What if, like in school, you get "degrees" for achieving things within the organization? If you launch a major new product successfully, you achieve a "master programmer" honor, and the associated pay benefits. This doesn't necessarily give you any right to control others in the organization, but it rewards employees for stellar performance. They can then put that on their resume if they go to another company.
I would argue it is a little short-sighted to say that the company can exist in a vacuum, when every other company in the world, for the most part, operates with a title. That doesn't mean you have to play that game within the company, but you should at least accommodate employees' concerns that they work for you for 10 years, and then can never get a comparable job because it looks like they never advanced. If they stay in your good graces, it probably isn't an issue, since I'm sure you will give them a good recommendation. But if not, they could be in big trouble when they go to find a new job.