That might be true, because he was the only runner ranked No.1 in 800, 1500, 5000 and 10000m, but other greats like Kenenisa, Geb or Kipchoge also had a great range from 1500 to marathon. For Geb and Kenny B. i think they were capable of sub 3:30 1500.
People are also throwing names such as Choge or Lagat, but in comparison with previous - they are second-tier athletes (no WRs, no Olympic golds).
Someone said Webb - but he had only one good season and is barely third-thier athlete.
I'll tell ya that you all forgot the man who had perhaps even greater range than Aouita and that was Kip Keino. Like Aouita, he went down from contesting 10k at the '68 Olympics to steeple and even 800m in '72.
Apart from his WRs at 3 and 5k in '65, his legendary 1500m gold in Mexico that is still the greatest Oly performance in 1500m final, three CG golds, he run 28:06 10k just before the Games - third fastest ever for the distance, still 27 secs behind Clarke's WR.
In '72, just before the Olympics he ran 800m PR of 1:46.4 - only 2.1 seconds behind existing WR and than won another Olympic gold in 3000msc, missing the WR by 1.6 secs in a tactical final.
If you translate his performances to year 2020 his times would be abnormal
Look at the line -
800m - 1:43.0
1500m - 3:27.8
mile - 3:45.1 (run 3.53.1 in altitude race in Kenya on cinders)
3000m - 7:20.6
5000m - 12:43
10000m - 26:38
AND
steeplechase - 7:55.2
That was Kip from 1965 to 1972.
Sadly, there's no runner nearly capable of that today.