I think most people don't collect prewar HOF RC's because it's too expensive and rare. Last year, someone tried to come up with a complete HOF rookie card set for the PSA Set Registry. However, many of the card are obviously not rookie cards (e.g., 1933 Goudey for Ruth). However, most of the post-war cards are the correct rookies. I think the creator was going by the Beckett guide for rookies using the "nationwide set" definition, and also trying to make the set more obtainable. The set composition is here:
Link, and there are already 17 sets on the registry, so it's gained traction relatively quickly. That's why I think that there is some interest for this kind of set. There should be interest in a better list than this registry, but probably would just need to be published somewhere like the PSA, SGC, or Beckett registries to become more popular. For example, even the Top 250 Sportscards set on PSA (
Link has some active collectors trying to complete the set even though there are some very expensive cards on that list such as the T206 Wagner, T210 Jackson, and Baltimore News Ruth. (Spence is at 98% completion for this set.)