It's just the nature of the market.
Little point in paying for ultra-light materials to save a few lbs, and then loading it down with heavy panniers and camping gear. Touring bikes tend to see a lot more risk and abuse than high-end bikes like getting locked up outside, and ridden in lousy weather and on unknown crappy roads. Bicycle touring/camping is an extremely economical way to travel - those that have the means to buy a 10k bicycle tend to prefer different accommodations than sleeping on the ground in crowded pubic campgrounds.