I saw a good post about this a while back, that referenced Cory Doctorow's concept of Adversarial Interoperability[1]. Basically, by making their product data -- i.e. the databases of how names map to grid references -- rather than a standard or a service, W3W locks out competitors by copyrighting the core capability. They have a monopoly over the addressing scheme, and interoperability is impossible. I think it gets straight to the heart of the problem.

1: https://www.eff.org/deeplinks/2019/06/adversarial-interoperability-reviving-elegant-weapon-more-civilized-age-slay