All the Apple stores worldwide as well as the online stores have stopped the sale and display of audio hardware from other companies. The affected brands are Longitech, Sono, and Bose. Only one third party audio is being sold and it is the Philips conference room speakers. However, the Beats audio devices are still being sold as they are a company being owned by Apple itself.
It is anticipated that all this is being done to prepare the ground for the upcoming Apple audio devices that will be released at the upcoming ‘Hi, Speed’ event on which they will also be releasing the iPhone 12 series of smartphones.