I've actually been watching all the Ladybird update videos (because I'm absolutely giddy at the prospect of a new, open-source browser engine), and they compare their test passing numbers to other browsers, including Servo. And from their own slides, Servo is behind them, but not by much, and making progress at about the same rate.

Maybe that says it all, considering how much of a head start Servo had, but Servo also took a very long... break, as you said.