I do like the feel of the "old cloth", indeed. And I'm sure the modern cloth also serves great purpose. I recently used the Loro Piana "Storm system" as lining for a tweed overcoat and the results are fantastic.Some do indeed. This is the phenomenon that exists in basically every trade though in one form or another. Whatever the professional version of "old wives tail" is. Group think, verities, etc... Plenty of tailors understand the benefit of modern cloth too though.
I can tell you in terms of performance, modern cloth smokes old shit. It's not even a comparison. That's not to say there isn't a reason for using old cloth though. It has a distinct look and feel, and if that's what you want, then that's what you want and it can't be replaced. Also, maybe a pattern or weave that doesn't exist anymore. But in terms of sewability, wrinkle resistance/portability, breathability, how it sets up, quality modern cloth is light years ahead.
Now, when you make all these assertions on the second paragraph, would you mind explaining further where they comes from? I've never heard a tailor say "I hate working with old tweed/worsted/blah, it's impossible to sew, it wrinkles like paper and it doesn't breath at all, all this new stuff is awesome to work with and I vastly prefer it".