If I believed that it was that simple, I'd agree totally with what you suggest. My point - incompletely made - is that "age" is not the sole issue. In fact, it's largely irrelevant since as I explained, it's damn near possible to run current cars in IT as things stand. As further evidence, consider the many examples of National classes that get no real attention from manufacturers.
No, what matters is "popularity," and we could get POPULAR enough for this to be an issue, even absent National status or a championship. We need to identify what REALLY insulates the rules from manufacturer meddling and focus on THAT, rather than get distracted by what events are called or what year the participating cars might be.
Kirk (who's going racing NEXT weekend)