Engine monoculture is a problem requiring deep pockets to fix. Servo was spun out but I don't think it has a single sponsor who will gut it through to market. Blaming us at Brave for not dying on this hill is deeply wrong. We don't have the funding or people to do it. You should save your ire for Mozilla, for mismanaging Firefox and Servo.
I doubt Google will mess more than they have with Chromium, with Microsoft, Samsung, and Opera (not to mention Yandex) all using it. This is the way evolutionary kernels work (see Constantine Dovrolis's work). Get over it, and stop blaming the little browsers!