The 'old school' didn't do what they did because they wanted to, it was because they had to. Designers of those grand old horns of the RCA/Altec/Western Electric era used 15s in everything because they were the only drivers with enough displacement to deliver adequate power for the intended usage, which was primarily movie theatres. I'm sure that Harry Olsen would have used eights and tens if any had existed suitable for the purpose.