Haha, yeah, apologies if I made it sound like that. It's only after posting here that I've learned that there are people wearing heavier, tighter woven linen shirts for autumn/winter. Didn't know that, I only know the light weight, summery types. It's hot here, you know...
After much research i have made a few conclusions:
1. I was wrong about linen i was for some reason thinking about canvas.
2. Wool is far superior to cotton as a flannel shirt in pretty much every way from it's warmth to the structure of the fiber it is a better choice, unless you plan on absolutely battering it wool is by far a better option. Mountain climbers don't wear cotton fleeces they wear wool.
Appreciate your effort in doing research
And yes, as soon as physical effort is required, wool is way superior to cotton since it wicks away moisture and maintains its warmth.