Unfortunately, very little of this article is accurate.

The Apple III's RAM is located on a separate board mounted above the motherboard using a custom connector. The initial RAM connector had a design flaw that wasn't caught during testing and ended up shipping. The flaw caused the machine to intermittently lose connection to its RAM, and without RAM the machine obviously doesn't run. Jostling things around restores the connection to RAM and get things working again.

Apple redesigned the RAM connector and then recalled all of the initial machines through their authorized dealer network. Every motherboard was replaced, regardless of whether it exhibited problems or not. Apple continued to sell the Apple III for four years using the same aluminum heat sink for its entire run. During that run it was as reliable as any other machine on the market.

The Apple III never had an overheating problem. It did not contain chips that were magically able to unseat and reseat themselves. These were all just theories that people invented to try to explain the behavior they were seeing. The theories were complete fiction, and are laughably preposterous in retrospect. And yet, the theories continue to be repeated as fact 40+ years later.

The Apple III was an important chapter in Apple's history not because it was a dud, but because of the way it developed an untrue reputation for poor reliability that it was never able to shake in the four years it was manufactured and sold.

The "Drop Three Inches" podcast is a great listen if you want to more about the Apple III. http://drop-iii-inches.com