What is Manager ? A person who likes (or used to) to assign, control, supervise, investigate, sits in meetings, etc. I have this experience in big international companies, managers spend most of the time with internal issues - human resources, inter-departmental ones, processes & procedures, reporting to higher levels, preparations for exhibitions, speeches, and so on.
In small organization, that energy, knowledge, time, vigor, can be utilized by use those, directing to the market mostly. Human resource issues will be much less; inter-departmental issues will be transformed to fight with competition; reporting and meetings will be transferred to marketing research and approaches.
And also in big companies, people stay if not anonymous behind the big brand, at least in shadow. In small companies, the name of the person is more visible on the market. I mean for example " GE Corporation gets 20 % market share under management of Mr. John - to - Mr. John's Company gets 20 % market share".
all the best