You've selectively quoted the article. The full quote (emphasis added):

"When Moore’s Law slowed in the mid-2000s (specifically, single-threaded performance stagnated), we suddenly had to think about parallelization, architecture, memory locality, etc."

Your link is talking about transistor count. The article is talking about single-threaded performance. Today's CPUs are faster in large part because they have more and more cores.

> Your link is talking about transistor count. The article is talking about single-threaded performance.

But Moore's Law has always been about transistor count, not performance.

And more cores means what exactly in terms of transistors count?

It did in terms of the traditional more MHz (GHz) is better, but as you've correctly pointed out, not when it comes to actual compute.