On one hand, Sam's point is basically described by Paul Graham's essay on "Narrow and Deep" ideas [1]. You want an idea to have a few passionate users rather than lots of lukewarm users, because there's an activation energy to building a habit and if you're only lukewarm you're not going to get over it. As PG put it, "Sum that reaction over a whole population, and you have no users."
On the other hand, you have Geoffrey Moore's "Crossing the Chasm" [2]. This has the critical observation that early adopter & mainstream populations are different. About 10% of the population has an early-adopter mindset: they will try anything because it's new and cool. Those are the people Sam says you should be hanging out with in this article. But your experience with them doesn't generalize, because most people don't think like that. Most people are self-interested and have short attention spans: if it doesn't deliver clear value to them with minimal hassle, they aren't interested.
The set of world-changing products really exists in the intersection of these two worldviews. Products that had lots of passionate early adopters but failed to cross the chasm include Lisp, LiveJournal, RSS, VR (both times), and cryptocurrency. Products that aimed for too mainstream a market and only had lukewarm users include WebTV, grocery delivery, and smartwatches. In between are products like the iPhone, where the PDA market had been sitting in early-adopter limbo since 1991 but technological changes finally made it practical, or YouTube, where streaming video had been in early-adopter limbo since RealAudio in 1997 (?) but cell-phone video, Flash, and easy web uploads made it practical in 2005.