As to ordering of component importance: I think a combination of theory and personal experience will likely influence our choices.
Most of us understand that it's pretty easy to get accurate amplification and an accurate DAC these days, and that speakers (and room interaction) remains the biggest bottle neck to accuracy and sound quality.
I've had various personal experiences that re-enforced this idea. For instance the first time I heard Quad ESL 63s was in a pal's basement hooked up to a modest Dynaco ST-70 amp, non-name cables, and a cheap CD player. And yet the sound blew my mind and was paradigm-changing (first real experience hearing an electrostatic speaker). To paraphrase the old cliche "It's The Speaker, Stupid."
Another time was visiting a speaker manufacturer's house - John Otvos of Waveform. Otvos had is speakers designed with an aim towards accuracy, excellent off-axis performance, with the input of excellent speaker designers and the use of the NRC. His "egg module" designs were getting rave reviews. At his home he made a point of demoing his speakers (tri-amplified) powered by cheap "non-audiophile approved" amps (Kenwood IIRC) and no-name cables (he thought that was all B.S.) Well, the sound was startling. The system effortlessly outperformed so many of the super expensive systems I'd been hearing (many hooked up go gazillion dollars worth of amps/cables).
It was another moment re-enforcing how big a role the speaker play vs the other components. (I've also heard some excellent speakers that I owned that I sold to another audiophile. In his system he had them hooked up to ludicoursly expensive cables, power conditioners, amps etc. I didn't notice any increase in sound quality at all from what I had at home).
On the other hand, I guess once you've taken care of the speaker end of things (bought speakers you like) the more subtle contributions of other components can seem more prominent. And some of this can be of purely
subjective importance/evaluation. What may be important to you may not be to someone else, of course.
In my case, I found my tube amps seem to play a very important role in
my enjoyment of my system. A number of times I've put other amps (e.g. Harman Kardon, Bryston solid state) in to my system and the result was always that I found the experience less interesting, and found myself listening less and less to the system. One time my tube amps blew a fuse, I was lazy about getting them fixed so substituted our Harman Kardon amp. I found myself listening to the system less and less over time, and I attributed my lack of feeling compelled to sit down to just losing interest in audio. So I decided to sell my tube amps. I had them serviced/fixed and before putting them up for sale I put them back in the system to double check they were working ok. But I found myself utterly transfixed again, that smooth, unmechanical gorgeous sound was back, and I couldn't stop playing music. So I kept them...and have enjoyed my system ever since
Even subtle differences can have large subjective impact, if it's something you care about. (For instance, my friend's system sounds decidedly more detailed and vivid than my system in some respects, but it doesn't make me want to sit and listen for long periods of time - I prefer the tone of my system).
