Yep. I run into "enterprise" cloud environments where IPv6 is disabled, all the time. The sad thing is IPv6 is easier to understand than v4, just based on subnetting practices alone. The real problem is the average "IT" person doesn't understand hexadecimal.
Thing is, you can run ipv4 only, dual stack or ipv6 only. Ipv6 only won't work. Dual stack has a larger attack surface and is complex. Ipv4 works but costs a relatively tiny bit of money so far.
Why would you not use ipv4?