Keep in mind, these are two different networks, both with costs associated with running them. Those have to be paid someone.
VSC could do like other smart contracts platforms, i.e EVMs, and charge a transaction fee. If it did that, would that affect HIVE?
It seems that VSC already answered my question about this. You're also right, using EVMs to pay fees for each transaction doesn't seem interesting or right for a protocol powered by the Hive network.
Depending upon what is built on there, it could be problematic.
They are on the right path there.