Haha, I've sometimes wondered if I should make this exact same thread. What I've philosophized on this subject is that:
1. Many people haven't had any experience with GOOD quality EQs. The quality of the EQs varies a lot, some ruins the sound more than it helps (distorts, colors/changes pitch of the frequencies), most software EQs are bad such as iTunes, foobar2000 etc. In best case scenario an EQ simply adjusts the loudness curve, this works well with a good hardware EQ. Cheapest option if wanting to try out what a good quality EQ can do: pick up an Audigy 2 ZS 2nd hand for around $15 => install kX Audio drivers and use the built-in hardware DSP 10-band EQ.
2. The site is head-fi where many people are very theoretical and simply go by theory rather than using their ears. Audiophiles have it in their head, the way an EQ works like is something "bad" as you interfere with what the manufacturer or the producer of the music intended it to sound like. The only "clean" / proper way is to go for a headphone with that particular sound.
3. People are getting more and more convenient and expect more and more "plug-n-play" / Apple-like kind of motto. People are getting too lazy to fiddle around with settings, want everything served on a plate to enjoy directly.
4. The higher price people pay for a headphone the more they expect it to meet their prefers and don't accept the thought of "customization" to be the part of paid price.
5. People lack the skill/experience to EQ for a good result.
These are my major theories regarding this subject.