I guess they’re kinda forced to. Switch to Ubuntu or Debian for Amazon Linux 3 would be weird, but perhaps a smart choice.
So now they either have to support Rocky Linux, and hope others do to, or pay the full cost of maintaining a RHEL compatible distro.
RHEL7 is the upstream for AL2 and there is a LOT of heavy lifting done by AWS. Newer kernel, newer toolchain, newer glibc. They do live patching. They actually test all sorts of workloads before even a minor errata update. They took OpenSSL 1.0.2 through FIPS validation with NIST.
Just stop talking.