I've lost touch with the fellow, but I was friendly with one of the authors of a couple of guides a ways back. He told me the cost of printing books with all those color plates was getting too expensive to continue publishing new guides. Look at what the recently published Bruce Greenbelt book cost. Did I read that the book(s) on prewar lionel O gauge is expected to be 3 volumes, with the first costing $100?
How much would anyone pay for guides on recent production, how many would buy? Maybe I am mistaken, it's my impression that most folks buying recent stuff are more interested in operating, as opposed to collecting. (As always, to each their own!)