I think you missed - at least my biggest bugbear with synthetics - the lack of inherent fire resistance.
I mean you can spend literally hundreds of dollars on some new piece of equipment, pass within firing ranging of a camp fire and boom you have melt holes all over the place with nice hard edges to crack, cause irritation, render your item non waterproof etc. I know you can get fire resistant fabrics but I don't appreciate the health concerns from those toxic coatings.
I now won't pay top dollar on synthetic items, if I can live without it, for this reason. I look at an Arcteryx jacket and just think, yeah one camp fire and that's ready for the dust bin.