So these are the three browser engines we have: WebKit/Blink, Gecko, and EdgeHTML. We are unlikely to get any brand new bloodlines in the foreseeable future. This is it. If we lose one of those browser engines, we lose its lineage, every permutation of that engine that would follow, and the unique takes on the Web it could allow for.
The article came out long before Microsoft announced that they will drop EdgeHTML and adopt Chromium, but it is more relevant than ever.