One list or two?

In Big Macs vs. The Naked Chef, Joel Spolsky writes:

Why is it that the cool upstart consulting companies start out with a string of spectacular successes, meteoric growth, and rapidly degenerate into mediocrity?

This is a rather old article, but I came across it recently while reading his excellent book, "Joel on Software" (Apress, ISBN 1590593898), and it's an example of something I keep seeing.

At first glance, it's a straightforward list. The cool upstart consulting companies start out with x, y, and z.

Or do they? Actually, they only start out with x and y. Then, later on, they do z. Therefore it should be

Why is it that the cool upstart consulting companies start out with a string of spectacular successes and meteoric growth, and rapidly degenerate into mediocrity?