Because (even with that mod, which I also did with mine) the downside is the center of gravity rises, and makes the headphone more unstable when moving around or swaying).
I never had a problem with weight in terms of "ouch my neck" with LCD's. Their biggest problem is they have no ergonomic stability. You either get the headband digging into your skull through the headstrap. Or you raise the headband (by shortening the strap) and the center of gravity makes the headphone more unstable, and with this weight you can't even lean your head anymore.
Another issue is they can't be employed for long computer sessions. The pads start to compress slowly over the weeks to where the internal dimensions eventually start touching parts of your ear. Which makes you want to throw them out of window when you realize for cups these massive, you can't fathom why ANYTHING is touch your actual ears.
Audeze simply refuses to move away from this design (it's their brand in reality). At first I thought they can fix a few things, but then realize because of some intrinsic aspect, this design inherently cannot be salvaged unless they find a miracle in lowering it's weight by half or more. Only then can you do something with this moronic design.
Shame really though. With EQ, these headphones obliterate basically everything I've heard. Their ergonomics are so bad though, I envy any years-long owners that have no issues with them (though i guess i would be in the same boat if I didn't head headphones on nearly all the time in front of a computer).