The problem with picking apart something is we leave out the meaning from the whole. For example, leave out the salad dressing and you have little more than raw lettuce. Concluding that salad dressing is a salad's most critical element would be a mistake. The best dressing on wilted, tasteless, iceberg lettuce (a crime in itself) does not an enjoyable meal make.
When I proffered my list of the system's heart and left out source equipment and processors, it's not because I don't think DACs, transports, turntables, cartridges, and arms aren't important. They are. I can make or break how great Music Room One sounds by replacing DirectStream with anything else. But while the source and its processor are critical, just like salad dressing, their level of contribution cannot be debated out of context if we're to extract meaning.
A great transport/DAC played through crappy speakers and amp will sound worse than the opposite. And herein lies our first glimmer of truth.
Foundational products like speakers and power amplifiers are so essential to the success of our system that we tend to ignore them. Well, amplifiers anyway.
Speakers are hard to ignore. We look at them as music plays. Sound comes from them and changing brands makes a huge difference. Imagine plunking a set of electrostats in place of your horns, or dynamic speakers. Instantly they would look and sound different changing the character of your music and the decor of your home.
Power amplifiers not so much. They sit like unappreciated lumps we never interact with. It's one reason people love meters. We all know they're as useless as tits on a bull but we like them anyway. They bring life to our amps and animate their actions.
But it would be a mistake to underrate the power amplifier's sonic contribution to the system.