Ralph,
while your argument is fundamentally sound, only Jazz and Classical are typically performed without electronic support. Rock, Pop, Reggae, and even ELP always went through large speaker arrays with multiple crossovers and other electronic aids in the transmission chain. For acoustical music, any break in the frequency responce or -horrible thought- phase shifts in the audible spectrum severely interfere with one‘s enjoyment. So: ideally horn or other single driver systems, if need be two-ways, anything more complex usually doesn‘t get there.
I guess I am preaching to the choir given your OTL design philosophy…