[Cryptography] Bitcoin - closing the coin

[Garlo Nicon]

Many times you can read that the Genesis Block is the first block.
However, when you look at "previous hash" field it is filled with
zeros. And each new block has more and more leading zeros, as
difficulty grows. Is it possible that in the future difficulty will be
very high and miners will create block filled with all zeros? Then,
this new block will become previous to Genesis Block, making the whole
block chain a ring like a snake head eating his tail. Will it be
possible to add any new block then?