The replica argument is that dot com has a privileged position today and needs a competitor with a similar position. But this answers just one aspect of competition.
Competition is dynamic and time is another aspect.
Dot com has first mover advantage. A replica will be always be weaker. The market will consider it second best unless the competitor offers something more. Consider, any off-line example. The differentiation principle seeks to ensure competition to dot com will add value to the name space not imitation.