If it's an opt out feature then it may just take time for publishers/devs to realise... or they just give it some time then opt in at a later date.
I'm sure some indy devs may keep this kind of feature primarily for increased exposure (maybe some altruistically) but for most if it starts being used by too many people they may just opt out of it at a later date. (kind like when Netflix etc crack down on password sharing)
That said, looks like a neat feature, not something I will ever use myself but really does look like the best way for digital games to be shared similar to what was possible with physical. (at least assuming it doesn't block you from having a "family" from different IP address so you can share with friends)