Well... you can do all these things when there's no DRM at all. It's like counting up all the things you can do in a new modern prison, but it's still a prison.
You can do that sometimes...as long as your key isn't bound to a user account (Battle.net), and as long as you have the patience to get it working (mail the cds, give them your steam account password, find them a crack, etc). Some of those restrictions are reasonable and some aren't.
My point is that good DRM can protect rights of both parties , but never does. Instead, if often restricts the consumer's rights in favor of the publisher. Steam comes closest to balancing interests, but falls short as well.
I can see where you're coming from, but in my view the general consumer won't put in the effort to exploit your model if you make it appealing enough. I've known people that rented from blockbuster|netflix and just made rips of the VHS|DVDs for their own collection, but it sure wasn't those pirates that destroyed (or is destroying) their business. GOG sells DRM free games and nothing stops me from giving it away to all my friends, but I still end up paying for a new "copy" when I gift one away.
It doesn't need to though, the key thing with the rental business model is it needs to be easy and convenient enough. It's clear that it's a rental in the name, but people will get pissed off if it's not easy to get the content and outlandishly priced, and just go back to BT.
My point is that good DRM can protect rights of both parties , but never does. Instead, if often restricts the consumer's rights in favor of the publisher. Steam comes closest to balancing interests, but falls short as well.