Competition makes more complete markets

Stumbling and Mumbling blog discusses the high transaction costs of finance and fails to mention Econ 101, competition.  Just to remind our author, he specifies that central banking must be a monopoly, so his assumption causes high transaction costs.

The unit cost of [financial] intermediation is about as high today as it was at the turn of the 20th century. Improvements in information technologies do not appear to have led to a significant decrease in the unit cost of intermediation.

I find this problem a lot, economists conveniently forget Econ 101 in central banking, mainly because they couldn't do the math 40 years ago.