There's not going to be a new browser engine any time soon. It's Blink, WebKit, and Gecko.

Ladybird is like two guys who don't want contributions from like 85% of developers. Servo is not going to be ready for another 10 years. Asking for any already huge, major, and complex project like KDE or GNOME to "just write a new engine" is absolutely insane, and demonstrates a deep lack of understanding in just how complex writing a capable browser engine has become. Jesus, not even Microsoft can do it anymore.

So, what'll it be? Demand the impossible, or play with the cards you're given?