Assos vs Rapha

a i agree, not all systhetics are cheap, polyester is.
b ventile cotton, or long staple egyptian cotton is better than any synthetic especially with a wax or resin coating, as woven polyester is not waterproof unless coated or laminated, gore use a ptfe laminate.
Smallfurry
malden mills in usa developed the fleece made from pop bottles for patagonia back in the early 90's and it is 100% good.
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TBH I was trying to illustrate how general a term such as Polyester actually is. In the same way as nylon tights and kevlar vests are both produced from polyamides. Although most polyesters used for clothing will be PET (polyethylene terephalate), so its not a bad genralisation.

Gore-tex is a laminate containing a layer of PTFE (very thin and fragile on its own) which is produced while applying stress in two dimensions. This produces small holes which water vapour can pass through. The hydroscopic nature of the flourine atoms however, prevent droplets of water passing through these holes.

BTW -
I do not own any Gore-tex (mainly for enviromental reasons, although TBH I would still recommend the Gore bike jacket).
I've got a malden mills fleece buff which I love (use every day throughout winter), and a Patagonia fleece jacket which is also great (unbelievable warmth / weight ratio). I also have a hemp/recycled polyester hard shell which is very breathable and reasonably waterproof.