For context the HD6xx were $199 pre-inflation and pre-COVID and imo that was a great deal for essentially the HD650s. I'll agree that lately the prices aren't as good as before.

I think we have different perception but imo the KPH30i lacked a lot of detail compared to the 6xx.

I have the KPH30i and even made a favorable review about them. Have the Sundaras too :P But they're nowhere near the level of 6xx. (Referring to the KPH30is not the Sundaras) (Sundaras I'd say...sound better in many ways) But my discussion is about the KPH30is

https://imgur.com/CDbYdpD

For me, personally, the 6xx will always have a special place in my heart because I use it all the time. Really great sound and also essential for mixing and mastering audio (for me at least). But to rewind it back, basically the original post is talking about how a pair of headphones (sub 30 dollars) are nuclear proof in a BIFL thread. But imo that means nothing if the audio quality isn't good and they aren't. Honestly if he mentioned KPH30is..or KC75s...I wouldn't have disagreed - because they actually do sound fantastic for the money and are technically lifetime warranty. :P But the ones that were chosen, ie Bluedios in the title post aren't good.