Does anybody argue that Google is negligent for not doing a complete rewrite of Blink, rather than doing the same incremental software development as everyone else? Did they suffer from their choice to use WebKit in the very beginning rather than do their own thing?

Every time google kills a project they are bashed for it, there is (was?) even a website dedicated to projects killed by Google. And anyway the core of Google isn't chrome, it's Google search

Why would they need a rewrite? Blink is the market leader.

Meanwhile daily driving gecko becomes a worse experience by the hour.

Doesn't matter how much slower gecko is when most of what chrome is doing is loading ads.