I am getting the feeling that Netflix's customer base doesn't understand why some titles are available on streaming vs DVD only (this is based on random comment

I am getting the feeling that Netflix's customer base doesn't understand why some titles are available on streaming vs DVD only (this is based on random comment reading). It is a very subtle difference, but it comes down to 'Netflix doesn't have the title' vs 'Netflix has the title but they won't let me stream it'. Admittedly, the much bigger motive is that they want to get rid of their dvd-by-mail business.