Okta has pre-built integrations which you can select from their catalog. You will only need to provide your cloud tenant name, or prefix and that’s it. No need to figure out and build vanilla SAML/OIDC integrations. Also many of them have provisioning implemented, again, you would only supply api token or service account credentials.
But from a high level perspective you are right, you can build the same with any competitor. It’s just the matter of efforts required