Apple appears to have discontinued the 21.5-inch Intel iMac

The 21.5-inch Intel iMac appears to be discontinued by Apple. 
Spotted by @tgod34748, the 21.5-inch Intel iMac is no longer available for purchase on the Apple Online Store. A quick check on the iMac comparison tool confirms that it is discontinued. 9to5Mac says the model has been removed from the Apple Online Store sometime on Friday, 29 October.
The 27-inch Intel iMac is still available for purchase, but rumours suggest that Apple will release a new model in 2022.
Source: Apple, @tgod34748 via 9to5Mac