The hatcheries are the sellers, and the people who stand to profit from the output of the hatcheries (the hotels, restaurants, fly shops, guides, gas stations, grocery stores, etc, serving the people fishing for those stocked trout, as well as the local and state governments who collect sales tax revenue on all of the above) are the ones who should be investing to guarantee that output. The reason they don't is because, so far, they haven't had to. The Federal Government has been giving them a free ride by supplying the fish that brings in the tourist crowd without them having to invest a dime. I promise that if I were operating a business that relied on fish being stocked by some hatchery, and I could generate $75 for every $1 invested (per the quoted studies) I'd d****ed sure be investing in that hatchery instead of sitting around relying on Uncle Sam to do it for me.
Fly fishing - it's cheaper than a bass boat!