The manufacturer warranty is 2 years for both the TP-Link[3] and Asus[4] OnHub models.
If there were a class action, it would be against TP-Link and Asus. These manufacturers would then take the losses into consideration before collaborating with Google in the future.
[1] https://support.google.com/product-documentation/answer/6279...
[2] https://support.google.com/product-documentation/answer/6314...
[3] https://www.bestbuy.com/site/tp-link-google-onhub-ac1900-dua...
[4] https://www.bestbuy.com/site/asus-onhub-wireless-ac-router-w...