Originally Posted by Leukybear

Material and construction. R&D costs.
A better example/ place to not skimp out on for comfort are bibs/ shorts, a higher end pair has more panels sewn together providing a more ergonomic and less restrictive fit that better hugs your body providing more freedom in addition to a chamois that is likewise with such bells and whistles as variable density foam, etc.
All of which require more man hours, materials, hardware, skill to produce.