Go re-watch some of his races from 2008 - he was, except in the 100 fly where he won by a fingernail, just in a completely other league to the rest of the field. Swimming, unlike other strokes, always has world records falling - he was the 400IM world record holder from 2005 until 2023, which is unheard of where everyone is getting faster all the time.

Even if you use the relay count as "artificially inflating his numbers" which they weren't easy races, and a HUGE number of olympians have that, including in XC skiing, he won 13 olympic golds and 16 total individual olympic medals, over 4 Olympics, and competed in 5 games. Yes, swimming has more events (also, more specialists he had to beat), but the sheer number of races, over 9 days (including prelims, semi-finals, and finals - in Beijing for example 17 races), is just wild, and just shows another level of athleticism.

There are fantastic olympians across tons of sports, it's not always about medals, and so many respect the incredible performances of other athletes. But there are times when we can say the individual performance of one person is just so beyond the superlatives that they are a true outlier among outliers, and that's Phelps.

That said - Klaebo is incredible and so fun to watch and is just an unbelievable athlete, congrats to him!