Control is one argument, but I'd go with the money argument:
All the big cloud providers like Google and AWS as well as the small ones like Hetzner do have an incentive to keep IPv4 going as long as possible. They can charge a premium for things IPv4 "because addresses are scarce". Charging a premium means more profit margin.
At the same time, they do not need to invest in more than lip service for IPv6 support in their offerings: No cloud provider has any comprehensive IPv6 offering, most services don't do IPv6. The edge ones maybe do, but there are always sharp edges, missing docs and general pain, pushing everyone back to IPv4 where the profits are.
All the big cloud providers like Google and AWS as well as the small ones like Hetzner do have an incentive to keep IPv4 going as long as possible. They can charge a premium for things IPv4 "because addresses are scarce". Charging a premium means more profit margin.
At the same time, they do not need to invest in more than lip service for IPv6 support in their offerings: No cloud provider has any comprehensive IPv6 offering, most services don't do IPv6. The edge ones maybe do, but there are always sharp edges, missing docs and general pain, pushing everyone back to IPv4 where the profits are.