As a returning rider, I was very happy to do a course, and followed that up with more advanced courses every year simply because I knew I was rusty after years away from it. Apart from that, my previous bikes had all been no bigger than 110cc, so I wanted some tips about handling bikes with engines ten times that size.
The high crash rate may not be entirely due to the bikes being more powerful. I suspect there is a bit of a "let your hair down" element in the crash frequency. But as the stats show, the older age doesn't correlate closely with the accident rate.
I'd have to agree with the idea of subsidising advanced courses for younger riders who are probably less able to afford the $300 or so that they usually cost.