Not a great comparison, because Netflix didn't build the tv and then charge you a subscription to unlock the feature ( yet ) haha.

I have heard of licensing being bought in groups and some content never gets actually published for whatever reasons, I imagine some of it's quite extensive and just gets lost in the shuffle.

Or sometimes they are after certain titles in the group and just never bother with the rest, who knows if that's true though.

Generally aren't the missing shows usually contracted to another service? Disney can't put them on their service until a previous agreement expires.