Also, I don't think that KV-2 in terms of overall cost is expensive for what it does - if ISU-152 is worth 260 fuel, then KV-2 is worth 230. It's worse at some things, like penetration (it's still at Jackson levels) or hp/armour (it's still at Panther levels), but it has it's advantages, like longer range or ability to shot over obstacles, that emphasise it's "mobile artillery" role. Obviously, if you'd use it as a regular tank, it's pretty expensive for what it does - but the same logic can be applied to a lot of different vehicles too.
And again, while KV-2 is fine, the doctrine it is isn't.
Its not really the fuel cost that is a problem here.
Remember KV-2 costed 440mp before. Now it costs over 600 in a doctrine most heavily penalized on menpower.
It also have worst survivability out of all heavy armor with only 800hp, yet costs as much as IS-2/Tiger except having considerably lesser stats while not providing anything over ISU, which still survives much better and performs better in both AT and AI thanks to scatter and accuracy that actually allows it to hit anything.
You've seen the yt clip, KV-2 have hard time hitting panther sitting in front of it. This thing was battered with nerfs on the cost increase patch as well as the whole doctrine was when relic kept increasing menpower and fuel costs for everything until it became not affordable for the doctrine.