And if Sousa were right, the country wouldn't now be full of clubs, bars, cafes and concert halls where live music is performed, and there'd be nothing to play on the radio (or, okay, download on Bittorrent). Music scales through distribution.
> And if Sousa were right, the country wouldn't now be full of clubs, bars, cafes and concert halls where live music is performed
Compared to Sousa's time, the country isn't "full" of places where live music is performed. It's practically empty.
In his time, every bar had live music every night. Today, most don't any night, and most of the ones that do only have it on weekends.
Even fairly small companies had bands - big ones had one or more at every facility. I can't think of three established companies that have bands today. (A group of people getting together to jam at the company party doesn't count.)
We may hear more music today, but people heard far more live music before recorded music caught on.