Can you say more about why you say the "real median" is hard to measure? It doesn't seem hard to measure to me, or any harder than a 99.99 percentile. Why is 50

Can you say more about why you say the "real median" is hard to measure? It doesn't seem hard to measure to me, or any harder than a 99.99 percentile. Why is 50th percentile harder to measure than 99.99th?