I guess that the wool is too expensive to card, spin and dye. People just don’t want to pay that much for a sweater....plus you can’t just throw it in the washing machine.
I think a huge bag of wool sells for about $2. Maybe one day.....
I think Pendleton and a few others still use wool and that wool sweaters, etc. are still big in Ireland, Scotland and some other places.
I have some wool suits, slacks and sweaters that I’ve had for years. Except for a few cashmere sweaters I’ve received as gifts or bought on sale the last several years, most of the sweaters I buy are cotton. Our winters are typically mild and we have cool days in the spring and fall and possibly a cool night in the summer. So, they work well and I can wash and don’t have to pay for dry cleaning. Bought a lot of wool items when I lived in Denver - winters were much colder, plus I don’t recall cotton sweaters being so prevalent back then.