Family share? I don't understand, what you saying is you split the cost between yourself and a family member? If that's the case I could do the same with physical. In either case I don't share my console, I don't have family members apart from my brother who play games and he isn't playing the same games I do, he only plays online games such as GTA/Fortnite.I buy launch games at $30.00 with family share. The same goes for any other game that I buy. Only have to pay 50% of the cost. Do you make more or less than 50% of the purchase cost of the physical game when you sell it?
With physical it's pretty simple in terms of money saving, KH3 is a recent example I can think of, brought it for £42, digital was £55, so already I've saved £13, then after a month or so I was done with it, wasn't thinking about going back to it, sold it for £30. With physical I played it, was done with it and sold it putting me at minus £12, with digital I'm £55 down with no option but to just delete it off my drive, can't sell it or make any money back.
That's a £43 difference which is huge, granted with KH3 I did sell it off early, with other games like Detroit I brought and sold it after about 3 months, but even then I still got back £20 after buying for £45, digital was about £50 or something. So yeah, much, much cheaper.