It is, but claiming that it was "killed by the US government", and suggest it would have became the dominant OS is dubious at best.

So it's not just clickbait-y, it misleading at best if not just a lie.

At a minimum, it was set by the Japanese Ministry of Education to be used on all computers in schools from primary through college --- if implemented there would have been an entire generation of Japanese students who grew up with that OS.

There was an entire generation that grew up in Japan that used Japan-only cell phones that were used nowhere else. The same thing would’ve happened with this OS, it would be used in Japan but nowhere else.

Yes, but aside from novels (in Japan), not much is written/created on cell phones --- an OS presumably would've had a development environment which might have caused the OS to continue on after education was done.

The title says that the US government /intervened/. As the article explains that happened, but also that that intervention wasn't the only reason why TRON didn't succeed.

The title should have been "Japan tried to build an operating system for the world, the US intervened although it quickly changed its mind, but a Japanese Windows PC seller used that intervention to boycott it". Or maybe just "Japan tried to build an operating system for the world, here's why it failed".