Here in the UK a digital game often costs 37% more than the same physical copy, sometimes even 50% but I prefer having my games digital but it's definitely not worth it unless it's on sale. It's unlikely that the cost of digital is going to go down any time soon due to relations with retailers. 

So my solution for the next generation of consoles is that when a physical copy is bought you have the option after installing the game on the hard drive to run the game off of that hard drive and tie it to your account, but in order to do this the physical copy of the disk needs to be in the console and the console will make the disc unreadable to any other console but that unique console (for obvious reasons)

Possible FAQ before commenting: (Added some extra) 

1. What if you delete your data for storage reasons etc and then want it back again? The disc willl still work on your console or redownload the game as it is tied to your network account.
2. What if your console breaks? The game will be tied to your network account so log in and download.
3. But then would I be able to trade my game in? No. Same way you can't trade in a digital copy.
4. But I like physical? Then carry on as normal. 
5. What If I'm not connected to the internet? You can play digital games offline on consoles.
6. My internet is unstable if I do this then have to re-download I might not be able to. Then carry on as normal and use the disc as normal.
7. But surely this is the original Xbox One plan? No. They required online to be connected at all times and there was no choice.

This is probably never going to happen but I would definitely love this. 

You're asking for writable Blurays. Not gonna happen.

I suppose, I'm sure encryption can solve most of those issues. 

So you're proposing the DRM policy that almost killed the Xbox One launch?

That's a strange scenario - paying more for digital? There's no physical product to manufacture, so weird.

Your idea makes some sense. Maybe Nintendo's weird new notion of selling a box with a download code inside will come to your region and help out, but whether that's a trend the other guys would hop on or not...seems unlikely.

Sounds a bit complicated to be honest.

No, Xbox policy still required the disk. It require online. And there was no choice. 

Okay, missed the part where you said it's an option. My bad.

maybe it's because I've been up 24 hours now because of work, but this part doesn't really make sense to me. What's the point of digital if you have to have a disc in the drive to run it? 

The UK as you know is odd in it's pricing. Competition drives down prices, PSN and XBL etc, don't compete with anyone and prices stay high at first until sales which are controlled.

I think the way forward is the same as films, games seem to be behind both music and films when it comes to moving to a more digital age. Films nowadays mostly include a Blu-Ray version plus a digital version through a 'Ultra-violet' account, it is done by a code. Use that code you can technically sell your blu-ray copy of the film. But that digital code is only useable once.

So in terms of games, you get a digital version of the game when you purchase a physical disc copy. Sell that game and the digital version won't go with the disc, it stays with you. If all things happen as they should, due to this, digital only games will go down in price as there isn't the idea you get both physical and digital copies. Game stores will offer less for your game and sell it used for less due to the digital part not being available but obviously people buying the physical part can only play it with the disc in the console. It will encourage people to buy new as well because they get the digital version supporting companies instead of giving more profits to Game stores as buying used is more appealing for some older games.

Of course what games companies would do it just sell it for more than the RRP now anyway, because some of them are greedy and don't get it.