Indeed, and in the recent gcloud updates I remember seeing messages about that they are migrating the whole gcloud to python3, most components already supporting/using python3 with a few remaining ones (like bq) where the transition is still work-in-progress.
Checking https://cloud.google.com/python/docs/python2-sunset/ and gcloud topic startup it seems these are the only remaining gsutil tools which don’t support python3:
Other Python tools shipped in the Cloud SDK do not yet support Python 3,
including:
â–ª dev_appserver
â–ª endpointscfg