I think all people who are actually building something knows that they bring nothing of value especially when you weight the opportunity costs, but that does not really matter.
I was previously a "consultant" (I sat on a professional services arm of a tech company). We sold a tool that was very powerful, but often required a customization for each individual client in order to unlock the true value of the tool. Once it was customized, it still required ongoing maintenance but significantly less effort.
We offered professional services as we way to streamline the "customization" process as well as train the clients' staff how to operate (and further customize) the tool. We were experts with the tooling, so we knew the optimal ways to build things vs. someone who is just reading documentation & trying to figure it out from scratch.
Probably in the short-term, this was a large expense for the customer, but if you were to visualize an expense comparison over time, it was probably significantly cheaper than forcing your staff to learn everything from scratch first, then build out the customizations, all the while they're unable to make progress on their other efforts.
So, I guess it really depends, but this was my experience.
It Depends ;)
Treat a consultant like a therapist. Don't expect miracles. Expect to do your own work if you're seeking some kind of "transformation".
A lot of times there's an antipattern to using consultants, where orgs are at a loss to solve a big problem, and seek outside help. They put it on the consultant to fix, not themselves. They assume, wrongly, the answer is "out there" for some big brain genius to come in and fix then leave. They outsource their own internal lack of alignment between big stakeholders, instead of dealing with that conflict. They assume moreover that their own people, tools, processes, cultures, are bad.
A good consultant, like a good therapist, sees your org and all its warts and beautiful value (like a person) and helps guide you to your own change. Maybe as part of your team for a time, maybe as just an advisor, who knows.
But don't expect miracles unless you internally commit to change.
If you mean McKinsey group I’d say this. In Scientology there is a deliberate policy of putting very young people in certain high status roles such as “Ethics Officer” to break down typical social patterns and particularly force the application of rigid rules that more experienced people, particular embedded in the social milieu of the organization, might bend. By dropping young random into critical spots, McKinsey can overcome the resistance to change many organizations might have for better and for worse.
