Some business owners lack the drive and motivation to take their business to the next level. Some people get comfortable and are scared to take risks.
Small businesses remain small for different
reasons. They are almost always privately owned, some by couples,
brothers, father and son, etc "ma and pa" organizations as they used to
be called, where the owners own and operate the business and are not
interested in expanding beyond the limits that they are comfortable
with.
Keeping a business in the hands of one or two
owners/administrators and maintaining a work-load that can be handled by
a few people and that generates enough income to pay the bills and
insure the survival of your small business is not easy to do. If small
businesses survive and remain small it is usually because the owner
wants it that way and wouldn't have it any other way at all.