So I have done some reading. Apparently they're all done by a guy called Yoksi or something and all involve the same workaround. IE, a live Steam account that you use a trigger EXE to download the game and updates with and then a hack to tell Steam you are playing a free demo version. So you're probably right, Steam will no doubt patch this out and we will be back to where we were two days ago with Denuvo.
Thing is I really wouldn't want to go to all of the aggro to run these games any way. It obviously involves using a fake IP to play from and I would bet there are tons of divvies out there who didn't do that and will probably end up losing their real accounts also.
Is it really worth all that messing around for the sake of £20-£30? These games are not what you would consider small either. Between the three of them you're looking at over a hundred gigabytes in data to download too.