Order back issues of Sterophile's Recommended Components for each three years since the magazine started making such a list. This will give you plenty of names of designers/companies who've had their dreams crushed. If your library contains copies of Audio or High Fidelity from the middle of the last century, you will find many names that no longer exist or exist only as a shadow of their former selfs.

If you figure out how to survive in this industry, bottle it and sell it.

I'll try and help a little.

Rule number one in my Hi Fi life is: if I buy it, the company is doomed.

Man, where to begin.

PS Audio. Makers of high end components that seemed to sell well and critics liked. Had very well regarded gear. I bought their Lambda Pro CD CD transport just before they went defunct. They sourced their parts from Phillips, but then Phillips quit making those parts and PS Audio was gone, so no stock of parts. They've since returned to life, but I'm a little wary, given past history.

Apogee Loudspeakers. There were, to me, the creme de la creme, so I bought a pair. Soon thereafter, they went belly up. Actually, I heard A/D/S bought them and shut down the parts of the company they didn't wanna bother with. Luckily, a very nice Australian guy is trying to resurrect the brand and is starting to offer support.

Superphon: Used to make a giant killer amp and preamp, but then I went and bought the Revelation II Space Case preamp and thereby killed the company. They are trying to come back, as well. I think they currently offer just a passive preamp.

Audio Alchemy. They ruled the waves of affordable Hi Fi in the early and mid nineties, very innovative and great bang for the buck. I did them in by buying their DTI Pro, DTI Pro 32, and DDE 3.0...and a bunch of related power supplies.

(I'm not sure where Gary, one of their driving forces landed, but he seemed pretty cool. Dusty Vawter was part of the company and he hit a home run the next time up, as well, with Channel Islands Audio. A great guy makes a great product - Dusty would be a great guy to interview.)

Seriously, though, I mention these companies because each one seemed to be a success in the marketplace right up to the time of their demise.

Other famous flame outs:

Acoustat. They made electrostatic speakers and electronics, peaking in the late 70's and dying in the mid 80's. I killed them by buying a pair of 2+2's.

Looking up the saga of Mobile Fidelity would give a good review of life, death, near resurrection, living death, almost death, almost alive, and nearly feasible existence in Hi Fi.

I'm sure others will add more!

Dead:

Dahlquist - Jon Dahlquist designed the first (or one of the first) time and phase coherent speakers.

Dunlavy - Excellent speakers (also time and phase coherent)popular both among studios and home high end. John sold his company and within a year or two it was gone.

At least Buddha didn't kill them.

Paul McGowan of PS Audio is very approachable. Register on their website and ask him personally. He will likely respond with some thoughts of why businesses like his live or die.

Sonic Frontiers...although you can still get repairs/upgrades though Parts Connexion in Canada.
Grace cartidges.
Perpetual technologies does not seem top be around anymore.
Wollensak...8 Track player/recorders de rigeur during that heyday.
I must take partial credit with Buddha for Audio Alchemy's demise.
I also have Acoustats and Apogee's, but I purchased them used well after their departure.
Finally, Lazarus audio out of southern Cal made a great Cascade pre-amp as well as amps...has not been raised from the dead!

www.avahifi.com 40 YEARS dudes, pretty cool in the industry, outlasted so many. Must mean he knows the industry, and knows what to do. How many "breakthrough" companies came and went? Even the great pioneers have faded, Hafler, Dynaco, KLH,AR. Harman has saved many great names DBX,JBL, D&M saved McIntosh, Philips saved Marantz, then sold it to a company formed when they did, D&M holdings, now D&M is saving some of the great old names, and not turning them into just another K-Mart brand, like Fisher, AR, KLH became.

SoundCrafsmen had some great inovative stuff, they came out with teh first consuer very high quality equalizer, then a bunch of inovative amps. small high powered, before Bob Caca' had his. SoundCraftsmen has long faded.

CROWN a great original high quality maker, still going saved by Harman also. Had one of the first high power amps. See Crown stuff everywhere in live events. Like Dynaco had their ST400 one of the first high quality high powered. Phase Linear, poooof all gone, just like all Bob Carver flops. Did i mention Audio by Vanalstine, out did most of em...40 years and still making great stuff, priced for mortals

Frank Van Alstine (of Audio by Van Alstine) is also very approachable and would probably give you his thoughts as to how to survive as an audio equipment manufacturer.