Konqueror, Servo and Ladybird have their own web engine.
Servo isn't a web browser, its just an engine. Ladybird isn't close to usable and Konqueror well, feels like 2005...
Technically Servoshell is a browser bundled with Servo engine.
What's wrong with 2005 where desktop user experience goes? Why is the new sexy only 'let us remove all user choice and customization, throw decades of stable desktop UI features like menu bars, tooltips, keyboard shortcuts and mouse optimized icons, simply stretch a mobile touchscreen onto a widescreen display with gigantic fonts and dumbed down icons and call it a day'?
Because you can only browse pages from 2005 with KHTML (Standards evolves and KHTML hasn't been kept up to date in that respect)