That would be like the W3C declaring that interoperable hypertext is not in the best interest of the Web community. Or the Linux Foundation declaring that the Linux being open source is not in the best interest of the community.
It would be utterly sabotaging, and in the case of the Matrix Foundation, the Foundation is independently regulated by the UK Government as a Community Interest Company - and so anyone would be welcome to complain to the regulator (via https://www.gov.uk/government/organisations/office-of-the-re...) that the Foundation was breaking its charter, and the Directors would face fines and/or legal action.
This is why Matrix is in a fundamentally different situation to Keybase, or Zoom, or pretty much any other communication project out there, and why we spent so much time (and money) setting it up properly as a non-profit Foundation.