Because the market doesn't make sense. Ever heard of the Hype Cycle? When Bitcoin was first made known to the public (when the prce shot up 5x to $200, and then 5x to $1000, so on). Bloggers and News reporters rush in to talk high heavens about how bitcoin is the next money grab.
Bitcoin is the only thing stupid money knows about. Stupid Money, money from people that doesnt really know what they are putting it into.
Bitcoin is worth so much not because its a true reflection it's value. But speculation.
Bitcoin is undervalued, yet highly overpriced. If you understand this you'd know why the price of Bitcoin doesnt matter.