Today Amazon corporation confirmed  that they are no longer supporting its Windows Phone app. And company also confirmed that they have no plan to develop a Universal Windows Platform app for Windows 10 devices. Below are words from Amazon Support

1. Why is the Amazon Shopping app no longer available in the Windows Store?
… The Shopping app is not available for Windows Phone for download. We recommend customers call via your mobile browser, where they have access to all the shopping features.
2.Why can Windows Phone users not download the Amazon Shopping App?
It is our first priority to offer our customers the best possible shopping experience, so our shopping app is no longer available for Windows Phone. We recommend customers call via your mobile browser, where they have access to all the shopping features.
3.Is a new Amazon App for Windows 10 in development?
Sorry, we have no information about our product planning.
4.Does this change have any effect on Windows Phone users who have already downloaded the app?
No, currently there is no impact.

And also we can’t blame on Amazon for this, as it’s hard for company to make mind for developing an app for platform which has less than 1 % market share. But somewhere we also think(expect) that company should release an UWP app for Windows 10 so that it will available for 300+ millions users and can use it.
At some places Windows devices are getting new universal apps and games in which some of them are also compatible with HoloLens (which is worth to note that) and at some places major apps are leaving Windows Phone. Hope so this all things will change in future with the growing universal Windows platform. And UWP will make to developers to think again to develop for Windows (ex. Barcoo app). So it’s just matter of time because UWP is just started. And I personally think that if the UWP approach get stepped in correct direction in future (also), then Windows 10 (Mobile) will be the major platform in future for developers.

BTW the Amazon is still available for download through direct link. Make sure that you hit following link to get this app on your device before it gets pulled by Amazon.

[appbox windowsstore 9wzdncrfj3vb]