I never heard the word "build" used in gaming slang until I started checking out the online 3rd edition community. (Which, by the way, I consider to be a waste of my life and I wish I could have the time and brain cells back.) I'm not sure if the "build" mentality in D&D existed before 3rd edition because I was still in high school when I played 2nd edition and most websites I visited consisted mainly of people's homebrew material for the game (including an excellent character generator that has long since vanished into the gaping maw of the internet)and no bickering discussion boards. (Yeah, I know there was usenet, but I never got into that.)
Anyway, "build" culture came upon us (my group) even in the early days of 3.0. Everyone was constantly dicking around with feats and prestige classes, buying anything that had new crunchy material. Favorite prestige classes were picked and characters were mapped out like the Soviet Five Year Plan. In fact, one of the first DMs I played 3.0 under encouraged us to find a prestige class we liked and map our character development to qualify for it at the earliest possible level. It seems like the build of your character became the objective of the game, and many of the lovely tribes of the internet would say "Yes, it is the objective." The whole point of the game became how to have an effective build. You didn't take something because it was cool or because it fit your character concept, you did it because it was mechanically more effective. We ended up with ludicrous rapid fire chain trippers, guys dual wielding two handed swords, a character who could add every single ability bonus aside from Strength to his Armor Class... and this was, admittedly, shit that people did just because they *could.* The Elven thinblade replaced the longsword because there was no reason for it not to. Character classes became totally divorced of any meaning and just became buckets of abilities that one could "dip" into. You took a level of ranger for the two weapon fighting (until they moved it to level 2 in 3.5 so you had to...I don't know, dip deeper?), you took a level or two of barbarian (but no more) to get rage and fast movement. When I voiced my opinion that I still viewed character classes as a representation of character profession and not as a special ability buffet I was called a retard. (Among other, less nice things)
It wasn't long before I abandoned the forums and the build-crazed and tried to run a game where you didn't necessarily have to have the most efficient selection of feats, skills, and other mechanical stuff to have fun. Of course, some of my players were still build-happy, and I'm not the type of DM to tell you that you can't do something just because I personally don't like it... so we had builders mulching through combat encounters and non-builders who often felt frustrated because, in comparison, their characters were useless. (Or so they thought) Meanwhile, the WotC machine churned out book after book, always with more feats, more prestige classes, the precursor to 4E's powers with Tome of Battle, etc, etc, ad nauseam etc. Finally I just put the books down and declared myself done with 3.X. I suppose you could say I was fatigued. I understood that I didn't have to use anything beyond the core books if I didn't fancy it, but my perception of the game had been changed; it seemed like just playing the game wasn't enough anymore, it was about obtaining some kind of mechanical benefit to one's character, which was often just a stepstone to another mechanical benefit, and so on. I'm not trying to get all OTW on everyone, but this just wasn't doing it for me, and I can't see myself returning to this incarnation of the game any time soon.