I always read them, but in a different manner for each. When they're endnotes I read them all after finishing the chapter that they go with. When footnoted I immediately read the note after every citation or after each page if the notes aren't extensive, since they're right there. I always prefer footnotes.

There are probably a combination of reasons behind endnotes prevailing 99% of the time. They are easier for the publisher like you say and there is the impression (truth?) that they distract & scare away readers.

Did UT Press allow you to go with footnotes for your Fort DeRussy study?