I guess the moral of the story is that if we want affordable food, we should eat local. It seems like half of the costs to the restaurant are associated with shipping the lobster alive.
What I found interesting was that the economics are affected by both spatial and temporal locality. The part about holding tanks that could keep lobsters alive for months to sell them out of season when prices were higher is a good reminder that eating seasonally can be as import for affordability as eating locally.
It can be locally grown or imported. It depends on the client. Some buy in bulk from local farmers, keep it (paying storage costs) then sell later.
On the other hand, I remember buying live lobsters between $5 and $8 a pound in a Boston grocery store. According to this article that would be a very small markup (and maybe sometimes lobsters were a loss leader).
Anyway, I think the markup at the restaurant is the highest. Maybe on the coast you can get a 2 lb lobster for $30, but that would be a ridiculously low price elsewhere. A steakhouse I went to last week in Nashville was charging $160 for a one pound lobster!
I actually found the middle-men involved to have a reasonable markup on the product. The price really gets jacked up at the restaurant where they have all of the overhead to cover.
So the moral to me is to cook your own food!