OSI doesn't own the term "open source" [0] [1]
[0]: https://writing.kemitchell.com/2019/05/05/Rely-on-OSI.html
[1]: https://writing.kemitchell.com/2021/03/18/You-Can-Still-Use-...
[0]: https://writing.kemitchell.com/2019/05/05/Rely-on-OSI.html
[1]: https://writing.kemitchell.com/2021/03/18/You-Can-Still-Use-...
Language is useful.
Trademark or no, enough people were on-board with the OSI and OSD at the time it became a well known and established term that we have a claim to it.
touch .well-known/open-source
Also the institution has proven to be stronger than one individual.
https://www.theregister.com/2020/01/03/osi_cofounder_resigns...?