This instance of openly-registerable nameservers is just one (relatively rare) subset of a wide class of dangling DNS issues [1].
Much more common is direct mapping of names to IP addresses on cloud providers that can be obtained by attackers [2][3]. Because of the scope and lack of global visibility that often comes with cloud services, an enterprise that uses is the cloud is very likely to have some vulnerabilitity like this under some subdomain.
Unfortunately bug bounty programs often blanket exclude any form of "subdomain takeover" as a valid security threat, despite the fact that they're easily exploitable once discovered. We have internal (and public[4]) data showing all manner of sensitive information leaked as a result of this sort of configuration mismanagement.
Ultimately, as others have observed, the current vulnerability disclosure landscape makes it far too easy for corporations to weasel out of acknowledging bona fide vulnerabilities, and of course ethical and legal expectations make it impossible for good-faith researchers to meet the bar of proof expected by these providers.
To others' comments: yes, these vulnerabilities are trivially exploited to provision TLS certificates in practice, a risk that is unfortunately downplayed.
[1] https://dl.acm.org/doi/pdf/10.1145/2976749.2978387 [2] https://escholarship.org/content/qt9r59r676/qt9r59r676.pdf [3] https://pauley.me/post/2022/cloud-squatting/ [4] https://arxiv.org/pdf/2204.05122