I disagree with this assessment. I actually think both 2e and 3.x did this the same way. In the early days of both editions, there were less "builds" and more free form playing. But as time went on, more and more options were introduced. Kits and special options for different settings started to take over as "builds" in 2e, just as Prestige Classes and splatbooks took over as "builds" in 3.x.
If you don't believe me, try to build a core-only, straight classed fighter in 3e. You may plan on following a single "build", but you'll only get to around level 9 before you realized you maxed out your feat tree and are forced to pick an alternate fighting style when you level up. Ditto for straight classed wizards, etc. Now, by the time Book of 9 Swords came out, it's a completely different story. Of course, by the equivalent time in its lifespan, 2e also had a million kits, splatbooks, and campaign settings, too.
I do think that the internet and made "builds" much more of a focus for some players, but I don't think there was anything inherent in either edition that was responsible for that.in