One aspect of getting young people involved is the issue of "entry-level" instruments. Like anyone else who plays just one or two instruments (mine's the harmonica...), I find this quite hard to judge

This is where the army came in handy. Generations of players could count on getting reliable ex-army-band flutes, bagpipes and brass instruments.

Schools mostly fail at communicating to parents that quality makes a difference. This is most obvious for recorders, where a reliably tuned, well-made instrument costs only a few quid - thanks to economies of scale these are the best value for money for any kind of instrument. But parents just don't get this and pinch pennies to get the absolute cheapest possible, which means unplayable rubbish. I imagine you'd get the same development with harmonicas if schools taught that.