And being proprietary, and only running on one family of operating systems.

Safari is proprietary and runs on one platform, not WebKit. Orion and a couple other browsers run cross platform.

I was referring to Safari here. I'm aware that WebKit is cross-platform, but it has vanishingly small market share if you ignore Safari, and it doesn't provide sufficient competition to browsers based on Chromium/Blink to keep the web from being a monoculture.

Safari has 20% of the market in The US?

In the comment you're replying to:

> but it has vanishingly small market share if you ignore Safari

Safari doesn't help here because it's proprietary and only runs on one family of OSes. WebKit doesn't have any substantive market share without Safari.

The context of the thread is

> I will mourn the lack of a non-Chrome browser engine with enough market share to prevent Chrome from unilaterally changing the web.

Ignoring Safari makes no sense as they are the ones preventing this.