There were no "previous HF chips."
HF only made one chip, and it greatly exceeded spec (400GH spec vs 750GH given enough power).
Then they ran out of money. Their misfortune is providing AM with the opportunity to catch up and dominate the 16nm frontier.
Sorry, not gonna let you sugercoat these guys, even though your core assertion is likely correct.
They "ran out of money" because their angry
As you very well know, the reason is because they sucked beyond belief at absolutely every other aspect of the business: board design, logistics, customer service, FTC compliance, funds management, PR, customer service, strategy, damage control, legal matters, board design (yes, they sucked at this at least twice), and last but not least: customer service.
It's a real shame that despite HF being good at chip design, they turned out to be far far better at pissing off customers and screwing up PCBs.