I was puzzled to see the iMac G4 in that list since it was only one phase in that Apple desktop line, which became THE Apple desktop line. The big deskside units are still around but only in a high end pro model for graphics and animation.
As for Betamax, that was a marketing failure not a technical failure.
In most cases, the so-called turkeys were fairly predictable. Either the product was different from where the mainstream standards were heading, or the product was quickly surpassed by another, and/or, in most cases, the product was offered by an overly greedy company that wanted to keep it all inhouse, and the world passed it by.
Beta fits this to a tee. VHS, from the beginning, supported longer recording times (2 hours vs 1 hour, initially), supported stereo audio, and was licensable. (The stereo sound feature was soon replaced with the HiFi versions of VHS, and Beta too, all of which had stereo audio. But in the original low-fi versions, VHS had the stereo and recording time advantage, and therefore my support.)
ATM is another example. While it was the only game in town originally, for anything faster than 100 Mb/s, the virtual circuit nature of cell switching wasn't where the Internet was heading. So packet-switched techniques like Ethernet soon caught up with ATM speeds, and the rest is history (although ATM is still used in the WAN).
Related to this, ISDN and BISDN. Remember them? Packet-switched Internet Broadband access took their place. Because circuit switching, virtual or otherwise, was not where the connectivity field was going. Too much state info had to be retained. Way too complicated, eventually.
Intel and IBM CISCs soon caught up with Alpha and the RISC CPUs. But they were glorious in their day, weren't they?
Steve Jobs had the genius of turning Apple into a company that sells fashion-setting gadgets to Gen X and Gen Y. Had it not been for that, Apple would have been a shadow of its current self, IMO, as it was before Steve took the reins again.
No list of technology turkeys would be complete without Microsoft Bob and the IBM PCjr.
The IBM PS2 architecture is pretty close to a turkey, though maybe not quite. The microchannel bus didn't take off and everyone else moved on to faster processors before the PS2s did. They were pretty amazingly put together with mostly snap together fastener-less construction.
May I take a side trip and talk about service stations not checking oil or washing windows? When marketeers asked consumers if they'd buy from such a station, their response was an overwhelming, "No way!" That is, until some stations did just that with gas a few cents cheaper. People voted with their pocketbooks.
That was the same problem with VHS and Beta. Beta was far superior, but it cost more and recorded less. It was great for recording movies, but for time-delaying "I Love Lucy"? Get real.
Every time marketing makes a comment such as, "The customers won't buy it without ..." I ask, "What are they willing to pay for ...?" Some features almost come for free, but most do not.
Sure, a few people will buy luxury cars, watches, and techno-goodies just because of the snob value. Most of us are content to go to Walmart or Fry's and pay a lot less for just the features we need.
The trick is, ask the right questions. Don't get overwhelmed with 'gotta have's'. They're traps - turkey traps, if you will.
As another side note, the superiority of Beta is pure urban legend.
First off, if the Beta image was better than the VHS image, it was only because the initial Beta tape speeds were faster than the VHS speed. That's why VHS could manage 2 hours, where Beta could only record for 1 hour. But that advantage went away soon enough, as Beta and VHS went to multiple hour recordings.
Another technical difference is that Beta did not move the tape away from the heads, when it was put in rewind. Which is why all those stand-alone tape rewind trinkets were sold (even to hapless VHS owners, of course, gotta make a buck). To keep the tape from depositing oxide and wearing the heads, when rewinding.
The bit about stereo sound I already mentioned, which VHS supported, at least in their format, if not in all the players, from the beginning (and Beta did not).
Beta failed primarily, I think, because Sony wanted to make all the machines (i.e. they were more expensive), and they recorded for fewer hours. That's hardly a winning proposition. They never caught up again.