Totem, Avalon, Audible Illusions, and Well Tempered all still have major consumer profiles. In fact, totem is the highest volume Canadian speaker manufacturer.
Many audio companies come and go based on consumer tastes and finances. Others, like @knotscott pointed out, dissipate once their owners/designers leave. Blue Circle comes to mind, as does Clear Day and, more recently, Herron now that Keith is retired. Or Merlin speakers once their owner died in 2015.
Others, like Halcro or Cairn, were badly conceived and faded after the initial advertising blitz.
And I think many audio companies are similar to music artists like Mindy Smith, Cassandra Wilson, or Pet Shop Boys: After an initial splash, they build a steady career with a steady audience. Think Acoustic Zen, Decware, PSB, Canary, and Channel Island.