The problem here is the language, "consultants" have earned a bad reputation from a cost point of view, tax point of view, work point of view etc. Consultancy has become a dirty word!
The reality is many mid to large size companies use consultants, whether they know it or not, or actually call them that. When you look to external suppliers or individuals for expertise or solutions, there should be a consultancy element being carried out in any project or work, that is why you go to the experts.
Most consultants do not make decisions, they look at problems/client requirements and present possible solutions, these will often differ depending on budget, resource etc. The client/company then has to make the call based on the options presented.
In our business, online lead/sales generation, we offer consultancy as standard, as otherwise we couldn't help potential clients achieve their goals. We don't charge separately for this, but the analysis and consultancy element is an integral part of the project.