This is a little different than the other elevator cost suggestions, so I won't rehash those arguments. I'll keep this short and sweet.
The elevator has SIX input ports, so give us a reason to use them! I'm sure the tier 7/8 elevator tier is expensive, but I think each elevator delivery should include all the costs of the previous tiers with an increase. This will give us a reason to scale up on all production and give us an adequate resource sink since all ore nodes are infinite. As it stands in EA, it's a little underwhelming, and I'm sure it will change over time as the game is balanced but I wanted to add my 2 cents.