Then, all of the people who already had 3DS but never logged into the eshop would have been the denied the free games. How do you suppose Nintendo would have regulated who had a 3DS prior to the effective immediately price drop date? Of course, Nintendo could have just NOT offered any compensation to early adopters but you'd just be bitching about that instead.
See, the problem is that there's no way to please you. Don't drop the price and sales suffer, meaning you're screwed in the long-run since that affects 3rd party support. Drop the price, increase sales, but you want compensation, except only for you and other early adopters. You're calling shenanigans on people who want to have their cake and eat it too but you want the same thing. You're just bitter because you can't which is ridiculous.
Nintendo made the right choice. They compensated early adopters when they didn't have to and they announced the price drop in advance to give early adopters time to log into the eshop had they not already. Sure, some people circumvented the system but Nintendo still nets those sales. It's pretty much win-win for them.