I thought about it when I built my system a few years back but I prefer air-cooled. 6 Scythe 120mm fans at 1900rpm pushing 110cfm each. I'm good. Sounds like a tornado everytime my PC's running... thank goodness for fan controllers. My comp never gets close to max temps even when doing a 360deg high quality rendering. Plus it's easier to swap hardware out when upgrading or replacing.
When you've got other hobbies like cars and guns... well, priorities and funds get placed elsewhere.