I'm sure it's just a reflection of my narrow experience, but the direct competitor of sound bars is not surround sound, but rather included TV speakers.
People who choose to make use of a sound bar are using it to enhance/replace the speaker array that the TV came equipped with.
People who use a sound bar do so because it checks as many audio needs as necessary within a simple setup. For myself and many others, its use as a quality bluetooth sound system is just as important.
Surround sound was never seriously considered, the sound at (and the subwoofer that came with it) are more than adequate.
You can watch the soundbar with only a TV?
TVs don't compete with sound bars, but sound bars certainly compete with TVs.