I also agree with their assertion that once you have a good source and an amp capable of delivering a clean signal, both of which can be had for reasonable money, the only thing that matters is speakers. It's the only part of the chain that makes a measurable difference to the sound.
The speakers and next is the room and finally the receiver/amp/transport. You can hook up different speakers to the same amp and theyall sound slightly different and then play them all back in a different room and get even more different sounds, but change out those electronics and the differences are much less noticeable.