Initially the (justified) change gave you ~18 months to implement necessary changes. Seems feedback was negative regardless, so they modified it in a way so current usage remains unaffected.
Re:Dear Google Cloud: Your Deprecation Policy Is Killing You
by aynyc on Saturday August 15, 2020 @06:21PM
(#24172930)
They didn't have a choice, their internal teams weren't ready for S3 SigV4. For example, EMR was not ready for SigV4. That means ton of customers can't use EMR.
Initially the (justified) change gave you ~18 months to implement necessary changes. Seems feedback was negative regardless, so they modified it in a way so current usage remains unaffected.