There is no inherent connection between demand for HBD and demand for HIVE. Yes you could have $10 HBD but that wouldn't imply $100 HIVE or even $1 HIVE without some way to channel demand for HBD into demand for HIVE.

Of course, it could happen as you say. Despite the fact that HBD and HIVE are largely two independent tokens, crypto markets (as with many markets) often move together. But even in that case, channeling demand for HBD into demand for HIVE would tend to increase the price of HIVE even more than otherwise.

Right now we are buying about 30000 HIVE ($10000 worth) per day, taking it out of circulation, and sending it to the DAO. That likely has an impact on the price of HIVE. It is roughly half of the amount of HIVE created per day (inflation) in order to pay rewards. If HBD did go to $10, we would be buying $70000 worth of HIVE (about 200000 HIVE at the current price) per day. That would likely have an even bigger impact.