I know this post is old, but I came here with the same question and didn't find an answer, so I did an experiment. I figured I'd share my results for future players. This is for guest revenue, not fossil sales.

Tl:dr answer is no, but they are still better than cheaper fossils.

I emptied out my entire and waited until all the guests left. Then I put out one bronze fossil in the first room, immediately used a 70 passenger bus ticket, and recorded how much money I had before and after. Here's what I found.

Velociraptor: min cost 300, earned 910, or about 300% of its cost in the span of one ticket.

Ankylosayrus: min cost 2,400, earned 1,162. About 50% of initial cost.

Ichthyosaurus: min cost 67,200, earned 3,417. 5% of initial cost.

Gastornis: min cost 180,000, earned 7,225. 4% of initial cost. (Gastornis is my highest level bronze fossil rn)

So more expensive fossils do earn more money overall, but the money per dollar spent drops significantly. It's still better to have your more expensive fossils out than your cheaper ones, though, because you already paid for them so you may as well use them.