Why are Smartwool base layers so much more expensive than the fleece-lined sets?

Smartwool pieces here run $85–$123 and use merino wool, which costs far more than the polyester/spandex blends in the sub-$20 WEERTI fleece-lined sets. Buyers paying the premium are generally after merino's odor resistance and next-to-skin feel; the budget sets win on warmth-per-dollar but rely on synthetic fleece linings.