The heater cover is that price for much the same reason high end glass is priced so high, you just can't get around labor charges. The price of the glass itself is inconsequential, the rest is based on the cost of hiring skilled glass blowers. Feel free to show the VHW heater cover to any glass blower and when you see their reactions, you might be able to better appreciate the worksman/craftsmenship that went into it.
The 5 inner marias is one of the key factors for why the VHW retains heat better than pretty much the rest of the "heavy hitter" vapes. It solves the key problem that the Herborizer, DBV, SSV, etc etc which is thinner vapor which stronger rips. Admittedly, not everyone like to hit their vapes super hard so it could be a moot point for some people, but for those that don't like to "train" vapornewbs on how to properly hit their direct draw vape, the VHW lessens the learning curve.
The maker of the Hot Glass Vape, the precursor to the VHW, is making his heater covers with GonG connector for $200 a piece and it wont include the marias, just a straight glass cover.