Joe on Nostr: That's not the case. My team can publish a lexicon, but we cannot go back and delete ...

That's not the case. My team can publish a lexicon, but we cannot go back and delete a published lexicon from the network in a way that invalidates existing data and breaks compatibility. The NSID control mainly extends to publishing new versions or making non-breaking changes, and that's all. It does not grant the power to retroactively delete already published versions that are in use.

Basically once a lexicon is published and in use by various folks and things (PDSs, App Views, Relays, client applications) then the team that initially created it no longer has sole control over its existence within the broader ecosystem.