

Dreamcast didn’t kill them, it was the Mega-CD, 32X, and Saturn that killed them. Launching three architectures over three years and not giving them space and focus burned a lot of political capital with developers (including those in house) and consumers. By the time the Dreamcast was out, it was already too late.
Which is a shame. Dreamcast was a masterpiece and so ahead of its time.
People like to forget Notch.