Lab glass is usually pyrex, which is a bit more expensive.
But the main reason is as Dadface says, the economy of scale. Smaller market, smaller production volumes, higher prices. Anything that goes into a lab ends up costing a bundle.
A PCR machine costs a few thousand dollars new, and if you think about it, it's not really a heck of a lot different than a toaster - in that it's mainly a heater and timer.