Why are Fi BTL 18s so cheap compared to Sound Stream XXX-18s?

noticed the Fi BTLs are only around $400 From what I've read on the Internet, correct? But brands like Focal and Sound Stream have 18s listed at like $1,300... Why is this? Also, since you are here, could you offer any speculation which is the best of the 3 brands mentioned? Or if there is a better brand than the ones I listed?