Hi Byron,
Here we have a very different access system for our rivers. On many there is no more fishing pressure than there was. One good example is the Chatsworth water on the river Wye in Derbyshire. The number of tickets available hasn't changed (the cost has gone up hugely instead). I was fortunate to be invited by a member some years ago (6 or 7), during the mayfly hatch (E. Vulgata). The most successful pattern was a white wulff on a L/S 8. Probably the same pattern that was used over the last 30 to 40 years. That shows that you are right in that fishing pressure affects the patterns needed.

Just down stream the fishing pressure is greater than it was. On that length the old patterns do not work as well. I can quote quite a few instances of this kind of change in fish behaviour. It is the direct angling pressure that does it. Leave the river without fishing it for a year or two and the fish are as naive as they once were. Just as we did a few years ago, when there was an outbreak of foot and mouth disease. There was no access to the water for a season. The next year the trout were noticeably easier to fool.

As to materials, well 300 years ago Stewart was tying his black spider with dark brown silk thread. Probably because he couldn't get a true black. I suspect that if he could get a good black then he would have used it. Classic salmon flies were tied with the materials available, mostly from the millinery industry. These were the latest materials at the time. Inventive fly tiers have always used the best materials they could get.

The proliferation in tying materials is in some ways to the detriment of the skill of fly tying. 15 years ago I taught a fly tying class at a local shop. Then the Fritz material came along. Quite suddenly all people wanted was to lash marabou and Fritz to a hook. A year or so later, when these people had learned that flash isn't the only thing that trout take, the shops best selling fly tying material was... thread, ready dubbed with hare's ear.

I shouldn't be surprised. I've just heard an advertisement on TV for an electronic game with which you can send, "Hand crafted communications to your friends". Funny I've been doing that for years with a pen and paper.

Cheers,
C.