That's a pretty archaic point. Blink and WebKit remain extremely similar, Blink is almost "WebKit-lite." Google remains one of WebKit's major contributors even after Blink since they share the majority of the same codebase.

The person above is correct, most open-source browsers use some WebKit based engine OR Gecko. The differences between WebKit, Blink, and to a less extent KHTML don't change that fact. They're still the same core-codebase.