amok: It is only "long term rental" in the sense that anything in this world is a "long term rental".
I have not downloaded all my gOg games, so if gOg disappears tomorrow I lose most of the games, so I guess that was 'long term rental'.
Lifthrasil: No, that's your personal decision. If you buy something but never pick it up, it's your own fault. But if you acquire something but aren't allowed to pick it up, then that's not buying. You can download any GOG game and play them on any machine able to run the software, no matter what happens to GOG. So these games are bought. The same is true for those games on Steam that are actually DRM-free - yes, I am aware that they exist.
But those games that need a running client that connects to some server, like those discussed here, can only be rented. Not bought. It doesn't matter whether the client is Steam or Twitch or anything else. As soon as the server that the client wants to connect to is down, you can't play 'your' game anymore.
Short version: there is a big difference between 'I didn't bother to backup the game' and 'The game cannot be backuped'.
aye, but it is still not rental. and there are other forces out of my control that can remove my access, such as my house burning down or a thief stealing my backups or my computer and disk getting repossessed while I was out.
the main thing here is that sooner or later you will lose everything, nothing is forever, but it does not mean everything is 'long term rentals' - it just makes the concept of rental meaningless.
The problem with Steam are problems inherent in DRM and should be dealt as such, without confusing it with other terms ("rental") making the whole thing pointless.