The usage in the article is that 64/128 bits is the addressing used for the blocks. A block is 512 bytes. So a 64-bit filesystem would actually be limited to 2^73 bytes = 8192 EiB = 8.6 billion TiB of storage.
No cloud vendor has a billion harddisks, that's for sure.
(The filesystem might only support a maximum file size of 2^64 bytes, but that's nothing to do with the capacity of the storage array)