Sill it's pretty scary to think that one single company could own 51% of the hash rate.
I'm not sure I completely understand the extents of it but doesn't it give them absolute power of decision over what is and what isn't recorded on the blockchain and how transactions happen?
There were be always other people who will mine. There were be always other businesses which will compete with Bitfury and will be always someone who will invent another better thing than that which have already Bitfury. As for the blochckchain cannot be made nothing that can affect it. He is totally independent and decentralized. Is the amount of all the transactions made from every person who send bitcoin from all around the world. So nothing can happen to it.