Human technical and behavourial processes tend to be additive in nature, not exclusive. Despite hearing constantly that X is dead, or Y is the new Z, humans consistently behave in an additive manner: A now accompanies X, and Y and Z are personal choices dependent on personality. Web2.0 collaborations will simply be added to 'traditional' art and in time become part of the domain 'traditional'.
But the nature of Web2.0 actually renders the question a contrtadiction in terms. Web2.0 is collaborative and networked, with no real centre and no clear hierarchy - such a situation can only increase personal choices and options available, and indeed intensify the additive nature of human behaviour and processes. Web2.0 collaborations cannot 'replace' traditional art precisely because they are collaborative.