Yes, AMC has fallen out of favor.
It's nothing out of the ordinary. Happens to audio brands all the time.
Go back 15 years...
How many brands that you were dreaming of back then do you still dream of now?
As I sit here struggling to remember, my strongest emotion is that I am not even interested in buying most of them today(those still around). Like AMC, many I will mention have fallen out of favor: Accuphase, Audio Research, CAT, Cardas, Classe, Duntech(Dunlavy), Dyanaudio, Fried, Hales, Jadis, Jeff Rowland, JSE, Krell, Linn, Mark Levinson, Martin Logan, Nestorovic, New York Audio Labs, Perreaux, Theta, VAC, Wadia, YBA. And, that doesn't even take into account the equipment that isn't of that status that I used to check out. Adcom, A/D/S, Apature, Apogee, Aragon, Audio Alchemy, AudioQuest, B&K, B&W, Bedini, Boston Acoustics, Bryston, Canton, Carver(Sunfire), Cary, Conrad Johnson, Counterpoint, DCM, Denon, Isis, Kimber, Kinergetics, Legacy, Luxman, MB Quart, MIT, NAD, Nordost, OCM Belles, Onkyo Integra, Mod Squad(McCormack), Paradigm, Proton, PSB, Quicksilver, Spica, StraightWire, Tandberg, Tara Labs, TDL, VMPS, VTL, etc.
Yes, a lot has changed. Lots of brands have fallen out of favor. Yet, many companies have taken their places. Alpha Core Goertz, Analysis Plus, Audio Aero, Audio Note, Audio Physic, Balanced Audio Technology, Bel Canto, Blue Circle, Clearaudio, Coincident, Eggleston, Electrocompaniet, Granite Audio, HomeGrown Audio, Hovland, JMlabs, Joseph Audio, Joule Electra, LFD, Music Hall, Musical Fidelity, Osborn, Piega, Rogue, Roman Audio, Sakura, Silver Audio, Synergistic Research, Totem, Wavelength.
In my opinion, we have never enjoyed such myriad brands and products as we do today. Most of what was available then still is(and still going strong), but there is also so much more. And, so many of the new companies are better. Infusing our hobby with a tremendous amount of new ideas, energy, and ways of looking at things.
Don't feel bad for the likes of AMC(which I am a big fan of), it's still there. And, if you looking to buy it new, you can get it at a good price. Their quality is fine, just that low end of the high end is a rough place to play. Audiophiles are fickle. And, because of the late 90's economy, we have moved upscale, on a grand scale. Wanting to have the best, most attractive, unique, etc.; something different. It's a good thing, as the money has pumped a lot of R&D into the hobby. Things have moved forward a great deal.
Be happy, as we are truly living in the Golden Age!