The problem with this article is not any of the facts or reasoning which is all very spot on. The problem is the tone. From the very opening of the title "Dear Client" it's hard not to read this in a sneering, condescending tone. At best, it preaches to the choir, and will never be discovered by the people who need it most.

A necessary component of a good client-consultant relationship is mutual trust and respect. If the client is well-intentioned but ignorant, then there is a much nicer way of educating them, on the other hand if the client is stubborn and arrogant then you don't want to work with them anyway. On the flip side, you should respect your client's expertise, not pretend like running a consultancy is the same as running other types of business.

I understand the emotional appeal of writing a screed like this, I've worked with my fair sure of clueless and bull-headed clients (eg. many realtors during 2006-2007 bubble), but if you are as good as you think you are you can't let yourself get dragged into this embittered attitude as it will turn off potentially good clients as well.