That is not correct. Bitcoin is by far the largest, but people also have non-trivial amounts in various alt-coins: http://coinmarketcap.com/
In terms of your Browser-analogy: Next to IE6 (Bitcoin) we also have Safari (Ripple), Firefox (Litecoin) and whole range of smaller players.
They all speak dialects of the blockchain protocol.
That is not correct. Bitcoin is by far the largest, but people also have non-trivial amounts in various alt-coins: http://coinmarketcap.com/
In terms of your Browser-analogy: Next to IE6 (Bitcoin) we also have Safari (Ripple), Firefox (Litecoin) and whole range of smaller players.
They all speak dialects of the blockchain protocol.