Any word on why Netflix is not offering Warner Archive titles? Lot's of great movies. They seem to be available at Classicflix.com, but I really don't care to join another service.
Warner Archive is pretty much an experiment right now, they may be avoiding rentals for the time being in order to force hardcore cinephiles to buy.
Also, they only offer one title, but it looks like they want to offer downloaded rentals, see: Honky Tonk.
ClassicFlix probably buys the dvds just like a regular customer, then puts them out for rental. WB can't stop them, the courts established the right to do this long ago (as "the right of first sale")
Netflix can't exercise first sale rights, as they need to stay on WB's good side in order to license their movies for IW. So if WB doesn't want a film available for rent, you won't see Netflix renting it.