There's a dangerous path where the companies are required to describe these transactions as "rentals", but that wont actually solve anything. If we require clearer advertising, we're going to end up with a world where everything is very clearly a rental, and there simply is no option to purchase. People will still buy the $40 "rentals" because it's their favorite movie and they want to watch it multiple times, and it's Friday night and they want to watch it right now.
I think people understand the situation when they "purchase" digital media. They know it might not last forever. They do it anyway. They don't like it though. They would prefer genuine ownership, but it's not an option.
We either need to outlaw these long term rentals, or break up monopolies until companies that are actually offering genuine purchases arise. Or we could do both.
We need to regulate more than just the wording on the "purchase" page. This isn't just a problem of wording.