This absolves SEGA of most of its responsibility for its own demise, which is, quite frankly, nonsense. No matter what the "hype" stated, SEGA is the leader of this collapse. Most posters here have nailed it! Mismanagement and being unprepared to take on more fierce competition is what did them in. In other words, they themselves were the biggest reason for their demise, not anecdote of "failed promises" from the PS2.
I should have elaborated more on that, because it doesn't absolve Sega in the slightest. It's just that the Dreamcast was their last chance after all their mismanagement, and the loss of sales after the PS2 reveal meant that their business model was doomed, as the Dreamcast couldn't save them anymore.
Also, it's possible that Sega would have gone bust anyway, since the company was bleeding lots of money and the Dreamcast was sold at a loss, so if the software sales wouldn't have gone up quickly, they would have been doomed anyway, the Dreamcast would just have sold better.
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454
The Steam/GOG key gifting thread: https://gamrconnect.vgchartz.com/thread/242024/the-steamgog-key-gifting-thread/1/