...t-shirts and hooded (no doubt cotton) sweatshirts -- in winter.
At risk of incurring disdain, I don't see anything wrong with that in itself.
We've got snow on the ground here and I'll be going out tomorrow wearing jeans, T-shirt and a hoodie - all of them cotton.
If that's all you have on a road trip in winter in the Pacific Northwest, and you get stranded for any reason, it's potentially a big problem.
Oregon is twice as big as England and has 1/30th the population density. 70% of Oregon's population is in one sliver of the state (Willamette Valley). You can walk a long way, you can drive a long way, and not find help. So it's prudent in remote parts of Oregon, especially in winter, to take steps to avoid freezing to death when the car engine stops running and you lose the heater.
I love cotton and live in the more temperate and densely populated mid-Atlantic, but all year long I have a warmer jacket (windproof/waterproof), gloves and fleece accessories in the car because even here in the mountains in
July where we often camp, its usually in the 50s at night, sometimes the 40s. That's 3700-foot elevation.
In winter, here or Oregon (where I am from - the Columbia Gorge), I'd not be driving far with just a t-shirt and hooded cotton sweatshirt.
I have limited faith in weather forecasts so am always prepared for rain and cold if going any distance from home. I watch the weather forecasts rather closely since we do a lot of outdoor activities. Rarely does the forecast state that there's a ZERO chance of rain. Seems 10% chance is as good as it gets.
Gloves, neck gaiter, warm hat, ear muffs, balacava -- these things take so little room and they're easy to keep in the car every day of the year. Throw in a waterproof parka.
They will greatly increase comfort if stranded in less than optimal weather.