This program has existed since past decade and not many router manufacturers cared about it. Customers wouldn’t pay extra for this logo and there is not value for this cert.
There are more extreme examples. For example, China is banning IPv4 for new networks at the end of this year: https://www.theregister.com/2021/07/26/china_single_stack_ip... In two years, certain sectors in China must be using IPv6 regardless of network age: https://brandergroup.net/2021/09/chinas-plan-to-begin-elimin...
Other countries aren't that strict in IPv6 enforcement, but it's only a matter of time before they will be.