I'm trying to figure out what you're really asking.
If you're asking if WGT is going to offer different (newer) items for rent when you level up than the non-rentable (retired) ones, then the answer is probably: yes, eventually. I'm guessing that the red "Item not rentable" text was probably put there by WGT during one of their recent updates, as a temporary measure, until they can change their rental programming to offer newer items that are actually available for purchase in the Pro Shop.
If you're asking if WGT is going to give you some free rentals later on to make up for the ones that you weren't able to actually rent, then the answer is probably no.