Fine, it happened... but you also have your app on 101k more devices than you did the month before so do something with that, flip your perspective a bit and take advantage of it.
Hell, before pulling out of the Amazon app store, release a new ad-supported version, and wait until a decent number of people have upgraded. Then pull out of Amazon's store. That should help defray the costs of the new hardware. Users can still do as the author suggested: re-buy on Android Market, and for users who had already paid for the app (not on free-app day), ask for a refund. Any serious user of the app will want to switch over to the Android Market anyway, so they can get later updates.
That feels slightly underhanded, but... eh. Server costs are real.
Yeah, in hindsight I realize that from the user's perspective, this really sucks. As a user who knows and understands the developer's perspective and how Amazon (intentionally or otherwise) screwed him over, I'd be sympathetic, but the vast majority of purchasers would not know any of that background information.
Hell, before pulling out of the Amazon app store, release a new ad-supported version, and wait until a decent number of people have upgraded. Then pull out of Amazon's store. That should help defray the costs of the new hardware. Users can still do as the author suggested: re-buy on Android Market, and for users who had already paid for the app (not on free-app day), ask for a refund. Any serious user of the app will want to switch over to the Android Market anyway, so they can get later updates.
That feels slightly underhanded, but... eh. Server costs are real.