I suspected it a few months ago, but now I can confirm: The Hue Tap switch is out of production and off the market. It has already disappeared from the German Philips Hue website, on promo pictures for accessories it is eliminated too. Upon request, Signify informed me that the Hue Tap is now a discontinued model.
This is not really surprising. After all, the Hue Tap is the oldest accessory for Philips Hue, it was launched more than six years ago. In the meantime, the form factor has become obsolete and the Hue Tap has been replaced by the Friends of Hue switches, which are now available from several different manufacturers – matching the design of classic light switches.
Currently the availability in the trade is still good
On the official German Philips Hue website the Hue Tap is no longer available for order, the product page leads to a 404 error message. And the Hue Tap is also no longer available in some other EU countries.
Hence the little note to you: If you still need a Hue Tap because the form factor suits you, you should buy one in the shops as soon as possible. At the moment, the availability is still good in the well known online shops, but this could change soon.