consider also the lesser demand for this stuff. when you don't mass produce them, you can't leverage economies of scale to bring the per unit cost down.
that may be true, but large operations like that sometimes also lease their heavy equipment and tools at a fraction of the full purchase cost to reduce project start up costs and financial liability (borrow less to start) until they can realize a return on investment.
this, like i mentioned in my previous post.
the tooling for these costs a lot as its not mass produced like the tooling for more common, publicly needed tools. which drives the cost up.
then the machines that make the sockets and wrenches you have in your box, probably wont accept the tooling for the larger stuff, which means entirely new machines. which can either be made in house like my company does, or they could be bought from other companies that used to make them for a huge cost.
add all of the extra costs together to make extra large and not very often sold sizes like 2 1/2" drive sockets, combined with the fact that you dont have the constant sales in stores and to the regular guy that drives the cost of other tools down. and you end up with a huge price tag. but its just the way it is. they probably did make back their investment some time ago, but the pricing isn't set so they make back their investment in literally a year or two, they may be in the hole in terms of production costs, man hours, etc, all to get started making that stuff. and they have a long term plan to eventually have it all paid for by itself, but that doesn't mean the pricing will change, it stays low enough that its not unwanted, but high enough that they will still see return investment in time