Effects of copyright costs on season programming?
If there is an effect, it is very weak. I constructed grids of performance counts for every title of twenty composers coming out of copyright in the last ten years, and the only discernable relationship was with the 100th and 150th anniversaries of the composers birth. [more detail on this]. Here are the plots of the three most prolificly performed composers, relative to the year their works left copyright:}
(NB: I do not have all of the death dates of the librettists on file, so the end of copyright is based *solely* on the death date of the composer. Sorry again, librettists)