$40 car tires can be compared to $10 bike tires. If you wanna complain about bike tires costing 40 bucks a pop, you'll have to compare them to car tires that cost $140. $80 bike tires = $250+ car tires, roughly speaking; that's when you get into fancy high-grip, short-lifetime rubber compounds and special construction.
One quick note to the OP -- when a description of a bike tire mentions Kevlar, it's almost guaranteed to mean that the bead—the inside "rim" of the tire that hooks into the wheel rim—is lightweight, foldable Kevlar fiber instead of a thin steel wire. Kevlar is strong and very low-stretch, so it can substitute for steel in an application like this. There aren't many bike tires that use Kevlar fabric in the carcass to protect against flats (besides, since it's a fabric, small sharp objects can still work their way through the weave).