The answer to the question is that while agencies have no cause to fear a lengthening procession of clients forsaking the traditional agency route, there's no room for complacency. The fact is that "in-house" creativity has always been a feature of advertising. Major advertisers, particularly retailers, have long run a range of services, including design to PR, from within. They may even split their media buying arrangements between in-house specialists and outside suppliers. But most of these advertisers also know the limits to what they can do themselves and what's best left to their agencies. To an outsider, it might seem strange that more clients aren't seduced by the idea of having a team of captive creatives. But if it's such a good idea, why don't many do it?
The reason is that quality invariably falls when creatives work exclusively on one brand and are denied the stimulation that comes from being involved in a broad range of accounts. Also, it's more likely that in-house creatives will roll over when their work is criticised and not fight passionately to protect a brave and innovative idea. And it's a rare client who has sufficient work to keep an in-house team perpetually busy.
Most clients know that an over-supplied ad market allows them to make enormous demands on their agencies. They know also that they would have great difficulty keeping and stimulating the diverse range of talented and temperamental people who work in agencies. The senior adman who once remarked that "agencies exist to employ the unemployable" wasn't altogether wide of the mark. Nor can even the most sophisticated client match the skill of media independents who are immersed in the media market on a daily basis and who know where the best deals are to be found.
Even companies that begin by doing all advertising in-house usually find the number of staff needed leads to a huge increase in overheads. This isn't to say agencies can sit on their laurels, knowing they will always be needed. Increasingly, advertisers operate in fast-moving markets. Woe betide any agency that can't act equally swiftly.