1) As long as agencies continue to seek out the top creative and strategic talent, their services will still be demanded. Of course, this would fall under the assumption that Agencies are able to recruit not only better talent, but a larger staff of talent than sites offering one-off services.

2) Agencies are ever evolving companies that will continue to adapt to the needs of the marketplace. This is necessary for any company to stay afloat,and agencies will continue to find new and better ways to provide more value to their clients.

3) Integration. Not only do agencies provide an army of creative talent, they have also evolved over the decade to offer more services under one roof than what the sites you’ve listed would have bandwidth for.

To your point though, high-cost agencies probably will become less of on option for smaller businesses — smaller businesses that do not support A&P budgets that would justify such a spend for creative. But for the larger marketing powerhouses of the world, agencies will continue to be a valuable resource. Also to support your point, it is likely that clients will continue to squeeze budgets of agencies, forcing them to provide more services for the same fee.

This will be interesting to revisit 5 years from now — some kind of change is inevitable.