The Forbes article starts off with the Apple Lisa, developed more or less in the same timeframe as the original Macintosh. The Apple Lisa indeed turned out to be a commercial failure, there's no doubt about it. However, looking at the grander scheme of things, the Lisa played an important role in the development of the Macintosh, Apple's landmark computer that introduced normal folk to the graphical user interface. Some of the concepts of the Macintosh were pioneered by the Lisa team, such as Quickdraw, one of the fundamental components of the Mac OS. In addition, as the stories on Folklore.org point out, the competition between the Mac and Lisa teams propelled both teams to excel at what they were doing. From this perspective, the Lisa wasn't a failure at all.
Forbes also dares to include the PowerMac G4 Cube. As regular readers will know, I am a huge admirer of the Cube, which, despite its numerous hardware flaws and high price, is a design masterpiece that really shows just how brilliant Jonathan Ives can be when he's given more or less a carte blanche. The Cube is, as far as I'm concerned, still the most beautiful computer ever made - and many agree with me, as it found its way to the New York City Museum Of Modern Art.
Taligent is also on the list, but it's not the only Apple operating system that turned out to be vapourware. Back in the '90s, before Apple aquired NeXT, it thought it could modernise the classic Mac OS to face the challanges of the new era, but it kind of failed. Copland became a massive failure, prompting Apple to go shopping for another operating system to base their next-gen system on. An Apple failure list is never complete without Copland.