And I totally agree with Mick James:
So perhaps the "challenge for consultancy" should be turned on its head. The real challenge is for clients, who so far have largely failed to design their businesses in a way that acknowledges the ongoing, if intermittent, need for outside assistance. Just as you wouldn't design a building without access to your utilities, so any major organisation should have natural interfaces for dealing with consultants. At the moment consultancy is still associated with a certain violence to the organisation, which is now being reciprocated by the increasing pressure from procurement professionals. One would hope that after a few more years of this argy-bargy, things might settled down a bit and that clients would have not just a clearer view of consultancy, but would have established a more explicit demarcation between the various levels of subcontracting and outside advice and assistance they employ.
Whether clients will ever attain this level of consciousness is debatable. At the moment the uncomfortable situation for consultants is that they work in an industry which is being constantly reshaped by people who a) have no expertise in the matter and b) don't even know they're doing it. Remember that next time someone questions your fee rates!
And the clients are being shaped by factors described in this post earlier, in addition to several others that are unique to the geography they're located in and the industry segment they operate in.