It really depends on what you want to do. By the nature of being self-directed, you elect what roles you want to play. I personally don't love the marketing and sales cycles, so my current business is B2C and I don't do any marketing.

Almost all growth was done via word of mouth. There are business models whose network effects lean in this direction. In order to use my product, you must bring along peers so it's inherently 'viral'. I fell into this by accident rather than by some grand design, but it became obvious to me after I saw it happen. Design a business in which the flywheel can spin without you, if you don't want to spend your time marketing.

My next business that I'm working on is B2B, so I'll have to have a much stronger handle on marketing and sales. But I'm more ready for that now, after a decade of running a B2C business.