I think High Power is slowing down for multiple reasons.

1) Attitude. Moreover that of the older participants. I've many clients in my shop mention this. Turns people off FAST.

2) Technology. Let's face it rifles,OPTICS and ammunition have come a long way in a relatively short time. A bit of "laziness" involved as well here. For most optics are "easier" and in general bear more fruit for less time involved.

3) Dynamics. High power is as square range and square COF as it gets. IMO, the newer generation competitive crowd thrives on "added dynamics" stress, short par times, themed stages, complex shooting scenarios.

Imo, this is why 3 Gun, and precision rifle competition such as the the Precision Rifle Series are growing leaps and bounds.