How far have ss amps really come in the last twenty years?

I think, there is no definitive answer.
On one side, the business lives from the impression that the latest design is better than the model before.
On the other side, you buy/bought brain. With some luck you own a unit done right. From design, layout or parts.
Even when you go to a more modern unit from the same designer, there is no guarantee that it will sound better. Different? Yes. But better?
After all my years with High End I think, most have done something outstanding on pure luck. They made something and it was a 10 out of 10.
The majority of Audiophiles want to invest money after some time. They want to change. And to justify the investment or to be King somewhere, they tell and think, yes, it is better than my former unit. And when it is more expensive, it has to be better. That’s the rule of the High End game.
Audiophiles, who go for a cheaper unit because it is better and talk about that, are rare.
But probably they know it better what is going on.
When i go to High End Shows the last 15 years, my impression was, 80% is for - expensive - ear cancer, 20% is good.
When everything will become better, this percentage should vary. But it doesn’t.

A couple of weeks ago, I had my Ayre amp looked at for a "noise" - "resonance" that I heard in my left speaker.  Ayre told me that the amp was performing well with no noise that they could detect.....I asked them to look further and do anything that they thought would improve the piece. I got the amp back after they replaced a number of capacitors, and other improved parts.  They also applied a tape to the heat sinks....the result was a better sounding amp...but the circuit itself wasn't changed.  (I doubt if the resonance tape on the heat sinks did THAT much). (the original "noise" prevails.)

I was wondering how long it would take for the "all cables sound the same" camp to chime in with the "all amps sound the same" nonsense.
Talk about an agenda.

@stringreen How old is your Ayre? I am surprised that the company couldn’t detect the ’noise’ on the left channel!! It is definitely something that they should have picked up, because IMO ’IF’ you can hear it, it should be something that can be picked up as a functional/technical problem.

@syntax Nice post! I think that in my case, Jeff brought out a model at the time that he didn’t skimp on..and that factor allows it to be so very competitive even today ( particularly after the mods were recently done).
Nonetheless, aside from Class D ( which I also feel was, and continues to be, a step backwards ( except for the lower weight and heat issuance) ) it seems there really hasn’t been any true advances in the ss amp realm.

Heat sinks are very resonant, in most designs. And, every transformer has an amount of physical vibration. Isolating both of these issues display an increase in sq. Roberjerman, you are a character. I am sure, at this moment, you do have more equipment than I, but I doubt very much you have owned more than I, or have been exposed to more equipment than I. You stated you were in a band, so I believe your ears are shot, and unfortunately, you probably did not use ear protection. You have a tendency showing up everywhere here, claiming a system you have " currently hooked up in another room " is as good as anything today. Examples are Quad 57s, DCM Time Windows, GAS Son of Ampzilla, etc. I know from my own ownership how enjoyable these were at the time, but to say they compete with todays products, well, I am sure there would be a handful of people to agree with you, especially with the Quad 57s. Older ss amplifiers sound brash, or dark, because of the parts used in the day, or some other characteristics of design. And, the constant trolling you seem to enjoy so much, on the power cord threads, stating they make no difference, making a joke of yourself, because I do not know of one piece of audio gear in your " collection " that has an IEC inlet. I am inviting people here, to read up on many of your posts, to show the pattern, and some of us already know. So with this I wish you the best. Enjoy ! MrD.