"Retired" Speed badges?

Shalom Math magicians!

I´ve got a question regarding the speed badges. There is the "Going Transonic" and "" ones. Got over 300 of those at the moment. I noticed today that there was two more, the "Sub-light Speed" and "299,792,458 Meters per Second."

Tried do a exercises really quick for getting 42 and 75 correct answers done. However i didnt recieve any experience nor any badges. So i checked more closly. On the Khan Academy wiki fandom it said those badges where "retired." I guess it means that they are not possible to get anymore? How come, I would really like to get the chance to collect them!

When where they available, and for how long? Also when did they became "retired?" Why retire those kind of badges, I understand "retiring" badges for certain years. But thos could be obtained anytime. 

Please make those badges available agin, I guess many more peaple would like to be able to obtain those badges again!

Thanks a lot for the understanding and help!

//Blessings, Richard.