The problem with this situation is that the more stores/countries that break the release date, the more incentive there is for other stores to do the same. The reason? They are potentially losing out to their competitors if the competitor is breaking the release date but they do not - customers who did not pre-order, or who simply can't wait for the game, are going to go and purchase it at vendors who are currently releasing. If you don't do the same, you'll miss out on all these potential customers. Unfortunately, now that the release date has been broken, there is basically zero incentive for any other retailer to adhere to it. This will continue, and probably get worse over the weekend.
How does the developer deal with this in future? Hard to say. There is a 'hard line' stance of not giving copies to retailers that broke the release date in future, but that also hurts the developer because it reduces circulation and potential contact points with customers in future (probably one of the reasons why retailers feel that they have more to gain by breaking the release date then by adhering strictly to it). A possible alternative would be for future games to be targeted that pre-orders (i.e. digital versions) of the game are unlocked prior to retail release. So, for example with Witcher 3, the digital copies could have unlocked when retail copies were shipped. This has a couple of benefits: firstly, it avoids retailers being able to jump the gun, because the benefit will be less when most of the 'super keen' people have already received their copies. Secondly, pre-orders means more money in the door prior to release, which is good for cash-flow (particularly in the case where they have their own digital distributor and have more control). The main down-side is that it's obviously a major kick in the teeth to retailers, who might kick up a huge fuss, but then that's the consequence they face for their behaviour. The other down-side is that it likely means that the game might become available in a less 'refined' form, as it will be harder potentially to make day-one patches arrive on time - but the console versions that are playing currently also lack this 'refinement' so arguably it is not a huge hurdle to overcome, particularly if the refinement needed is relatively minor.
Still, it's an unfortunate situation for the developer, and there are no obvious or easy solutions. Sure, I would love the game to be unlocked early for all customers, but I'm patient enough to wait as well.