I think you're basically right. Dr. Olive is saying that the $100 IE, when EQ'd to Harman curve, sounds better than 61 other IEs (presumably not all individually EQ'd to Harmon--maybe I'm wrong).That may not necessarily be true either. Dr. Sean Olive at Harman conducted a sound quality test of 61 in-ear headphones, with the most expensive one at $3k a pair. He concluded there was no correlation between price and sound quality. The "best sounding' headphone was a $100 pair EQ to the Harman target curve. So, if Dr. Olive is correct, we can get the very best headphone sound for under $300 USD (DAC + amp + headphone).
https://seanolive.blogspot.com/2017/02/twirt-337-predicting-headphone-sound_17.html
BUT what if you could EQ'd every tested headphone/IEM to Harman? I think that would level the playing field a lot, there may be some real gems up there between $500 and $1000. And then we're into @solderdude's issues that there's more to headphones than frequency response, like THD (or very narrow peaks and valleys that resemble comb filters that our brains will misinterpret as HRTF).