It would have been hard for us to get the real-world battle testing needed to get Servo's style system into shape without rolling it out in Gecko.
https://github.com/servo/servo/pull/16971 is an example of Bobby Holley, a Gecko developer (who's awesome, by the way) landing almost a full rewrite of the multicore scheduler, making tons of sites faster in Servo.
https://github.com/servo/servo/pull/16971 is an example of Bobby Holley, a Gecko developer (who's awesome, by the way) landing almost a full rewrite of the multicore scheduler, making tons of sites faster in Servo.