Yes these style of flies have lasted 100 or so years and will last another 100 - simply because they work when fished correctly. Fly tying and fly fishing are unforunately a sport of fashion and as long as anglers seek the unobtainable magic fly there will be swings from the victorian lavishness to more sombre patterns.
Personally I believe we are at the apex of the second victorian era, and soon the audience will grow tired of the glitz and fritx and indeed will react against the incessant display of patterns that adorns the internet - daily growing more bizaare and most utterly useless and at best one day wonders. Techniques in tying have long since superceeded any requirement to produce a fly to catch fish. In some ways a complete race to the bottom, and we will have worldwide a massive number of talented fly dressers that are to a large degree on any realistic level completely removed from the purpose of why one should tie a fly and what that fly is meant to imitate.
Yes, the strongest characters,and often for commercial reasons will convince others that their patterns and styles of fishing them are best. However they are on a perpetual treadmill. If for a moment they take the foot of the pedal another will pass them out and eventually most will be found out as perpetrators and facilitators of nonsense.
Glassjet wrote
But the internet has blown all that apart. Look at this forum? For us, the hoi poloi, the great unwashed (well me anyway!) there is now no need for geographic isolation. I can take my influences from the best fly tyers in the world! I can even talk to them! But what are the consequences of that? Will it lead to homogenisation? That the strongest characters will convince that their pattern is the definitive way? Will the local traditions survive?
Though it took me a long time to get here the sudden realisation that blindly following the tenets of "the strong characters" for many years was a complete waste of time, and that one is led down one blind alley after another. When it dawns on you that 90% of whats deemed to be essential knowledge is in fact at worst nonsense, at best un-necessary then it makes the application of the remaining 10% that much easier. And ones fishing should improve dramitically both in terms of catching and in enjoyment.
Will local traditions survive? Probably, yes - though well diluted.
Some here and for sure elsewhere are embracing the old ideas with growing momentum, I wonder why ??????


