Guaranteed.

Small business owners often do the work of multiple people!

You're the accounts department, the customer service department, and the sales department.

And when you manage to get a spare hour or two, you're the marketing department.

You work day and night to keep your existing clients happy, and your bills paid.

There can't be much energy left for the marketing.

Option1:
You can stay up past midnight, working on effective marketing strategies to grow your business.

Option 2:

You could hire more staff, train them, and hope they have some good ideas for marketing your business.

Option 3:

You could engage a marketing firm and hand over tens of thousands of dollars and have them do it for you.

Doing it all yourself is going to lead to burnout. It is only a matter of time.

Finding good staff is difficult, and training new staff is expensive. 

A marketing firm will not put aside its million-dollar-a-year clients to focus on a small business account. Your account will be managed by the assistant's assistant.