The second problem is that you are citing some pretty old information about how Sia works, and you are missing some important details that help bring the system together and secure it.
Is there a current and complete white paper?
I seem to recall mention of work on a new white paper but it has not been released yet.
There's currently work being put into improving the gateway code to improve bandwidth usage when syncing since numerous people were getting stuck and could not catch up as well as numerous improvements to the renter/host system to improve scalingto large numbers of files.