Saying they’re only recommended doesn’t mean you’re still in an ok competitive position without them. That simple. THey may not officially “penalize,” but that says little. It’s not an “if you feel like it.” Double that for any college looking for a level of awareness and drives. Certainly, that includes W&L and Davisdon.
And lower SES kids do take them. It’s not possible to generalize for kids who are qualified for a competitive college. What may shift is the expectation that kids in underresourced high schools match the level of scores found in top school districts.