Earlier quoted context omitted.
I'm not sure how that applies to electron beyond electron bundling an entire copy of chrome in every app. Electron has plenty of non-web APIs, plenty of non-web permissions, etc. You could do exactly the same thing with webkit's APIs.
The comment I replied to wasn't about bundling webkit instead, it was dynamic linking of what's available in the system. That's not possible because each web engine behaves differently, even if somebody reimplemented the non-web apis as a portable native library (actually, these ARE implemented like that). We're bundling whole chrome because it's a reliable abstraction that works the same on all systems.
As a framework, webkit has a stable abi as well which means electron apps would just work with updated system webkit, rather than needing to be rebuilt. Similar for JavaScriptCore vs V8. Unfortunately JSC’s API isn’t nearly complete enough.