I agree it does sound a bit of a hype but, around that time the "Selmer Sound" started to emerge as distinct to the other more 'spread tones' of the era. Radio was THE most powerful medium of the age, what people heard on the radio affected their whole outlook on the World, entertainment ,politics etc.
Selmer horns do record very well, they project straight into the mic. far better than the 'spread sound' horns. Remember back in the day everything was recorded 'live'-- technology compared with today was non-existent.
Bear in mind also, these developments in instruments 'projecting' and being 'Radio Friendly' were taking place in trumpet and brass manufacture, resulting in horns gradually becoming louder and more 'focused' Going back to Selmer saxophones---I suppose the zenith of these developments resulted in the Mk VI, the most focused sax and most copied by everything that came after.
These comments in no way reflect my own preferences, sometimes it's useful to reflect on the attitudes and perceptions of bygone times in that way we increase our understanding of the present.