If you can successfully eli5, that indicates thorough mastery of a subject. Stuff on the bleeding edge of physics can be grasped by a limited group of experts,

If you can successfully eli5, that indicates thorough mastery of a subject. Stuff on the bleeding edge of physics can be grasped by a limited group of experts, but nobody might have developed the 10th dan sensei level understanding yet. Maybe in 50 years we'll have great explanations of black holes and quantum mech that laypeople can grok.