It's a shame that people are still (incorrectly) using the term "class C" 15+ years since classless addressing has been address too. =)
Not all things that are better are free.
Citation?
(At some level, 128 > 32, so unless all the algorithms used for routing are constant-time over the addresses, IPv6 will always cost more. But if you add up a bunch of layers of NAT, that's not free either. So this argument boils down to "if nobody used the Internet, it would require less hardware to run". Well, yeah.)
As always, a happy medium is required. That being said, once you boot up another stack, allocate various caches, and have your engineers maintain an additional set of configuration, the costs come down. But for ~10k routes, the costs to route those ips is greater than routing v4.