In reply to The Norris:
there is a difference - maybe not X18, but significant.
high end stuff uses higher quality components ranging from fibres and treatments to thread and fasteners and dyes and stitch counts.
the patterning on expensive stuff is more sophisticated, and construction methods use better technology, often applied by more skilled workers that include sharper eyed quality control.
textile producers have vast ranges of fabrics and treatments to choose from, and the fancier ones cost more per meter to make, with different limits of amount available.
combining various fabrics in hybrid garments pushes costs up, as does combining construction methods.
different colours make things expensive too. note that many of these designs are made in lots of 10,000.
so yeah, a final garment may have 1/4 the prices stuff in it - but putting it together and onto a shelf adds up. the name on the label reflects that process; arcteryx, patagonia etc maintain high standards right from conception to a decent display area.
but then, 99% of users will never push the limits of a garment, doing things that a uniqlo fleece (or whatever) will perfectly cope with.