First of all, how in the world do you equate the regional pricing of physical goods to digital ones?
They are tied together by distribution deals with retailers.
Digital goods have nothing to diferentiate them per country other than some potential taxes.
Neither does electricity, but even from the same power plant that can be priced differently depending on where it is going.
On the other hand when I'm asked to pay more, that sure feels like I'm being ripped off.
Then don't pay more? I don't buy new point and click adventure games because I don't think the playtime usually justifies the cost, so I wait for a sale or price drop.
In Britain and Australia, if a majority of people refused to pay the asking price for retail games, then retailers would either lower the price or stop carrying PC games, which will have the same effect of lowering digital prices.
In the EU it would be impracticable to try to get supply and demand working in unison, but you could try to make fairness an issue with retailers, publishers, game journalists, etc.
FWIW I pledged more on kickstarter for a retail version of the game than the Early Access / release price, and don't feel ripped off, even with Russians getting a better price than I could get now or if I had waited for pre-orders.
It's good to have boxed copies but a medium to small sized company could opt to go full online if they wanted and just sell boxed copies at their own website, as collector's items.
In the case of D:OS, though, it is the distributors handling the localization, as well as guaranteeing a minimum amount of sales. No distribution deals would mean Larian would need more money upfront to do the localizations (so there would be less going into the game, or the localizations would have to be delayed), and rather than getting access to an established relationship with retailers, they would have to either forget about a significant chunk of the retail market, or try to build distribution from scratch.
Or it could at the very least dictate some terms.
Larian isn't in a position to dictate terms (if CD Projekt RED couldn't for the Witcher 3, I'm not sure why you think Larian could for D:OS). If the game does well, then Larian will hopefully have more negotiating power with their next release. They will at least have more information about retail vs digital sales and regional pricing; whether that gives them an argument against regional pricing is yet to be determined.
