Certainly they happened!!
The top-SIX 3000m times in world history all occurred 25 years ago and since then the closest anyone has come to the WR is 14.5 seconds back (such a small amount in a 3000m!!). None of them ever repeated the ability to run 8:06, 8:12, or 8:20 ever again, BEFORE or SINCE. Nobody has run under 8:20!!
Only THREE Chinese women in world history (outside of Ma's Army and outside of 1993) ever cracked the top 1100 times in the event and they did it all in 2000. Seems legitimate?
Look over this All-Time List and you will be convinced!!
1 8:06.11 Wang Junxia CHN 09.01.73 1 Beijing 13.09.1993
2 8:12.18 Qu Yunxia CHN 25.12.72 2 Beijing 13.09.1993
3 8:12.19 Wang Junxia CHN 09.01.73 1h2 Beijing 12.09.1993
4 8:12.27 Qu Yunxia CHN 25.12.72 2h2 Beijing 12.09.1993
5 8:16.50 Zhang Linli CHN 06.03.73 3 Beijing 13.09.1993
6 8:19.78 Ma Liyan CHN 03.11.68 3h2 Beijing 12.09.1993
7 8:20.68 Helen Obiri KEN 13.12.89 1 Ad-Dawhah 09.05.2014
8 8:21.14 Mercy Cherono KEN 07.05.91 2 Ad-Dawhah 09.05.2014
9 8:21.26 Ma Liyan CHN 03.11.68 4 Beijing 13.09.1993
10 8:21.42 Gabriela Szabo ROU 14.11.75 1 Monaco 19.07.2002
11 8:21.64 Sonia O'Sullivan IRL 28.11.69 1 London 15.07.1994
12 8:21.84 Zhang Lirong CHN 03.03.73 5 Beijing 13.09.1993
13 8:22.06 Zhang Linli CHN 06.03.73 1h1 Beijing 12.09.1993
14 8:22.20 Paula Radcliffe GBR 17.12.73 2 Monaco 19.07.2002
15 8:22.22 Almaz Ayana ETH 21.11.91 1 Rabat 14.06.2015
16 8:22.34 Almaz Ayana ETH 21.11.91 1 Zürich 03.09.2015
17 8:22.44 Zhang Lirong CHN 03.03.73 2h1 Beijing 12.09.1993
18 8:22.62 Tatyana Kazankina RUS 17.12.51 1 Leningrad 26.08.1984
19 8:23.11 Almaz Ayana ETH 21.11.91 1 Ad-Dawhah 06.05.2016
20 8:23.14 Helen Obiri KEN 13.12.89 1 Monaco 21.07.2017