These businesses do not plan their marketing activities or a budget for them in advance, so they decide whether they can afford doing something each time there is an idea. This results in the fact that each investment is not connected with the others as it should be and therefore is not part of a thought-out plan designed to reach certain objectives.
Of course, one might think that it is not so easy to know how a particular year might go in advance and therefore how much of the budget to use for marketing. That is true, but that is why the most organised companies revise their plans every three months. If things look good, they will invest more, if they do not, they will cut some of the expenses.
A plan is nonetheless essential for all companies, because if you want to obtain more results, all marketing activities must have the same objectives. Without a plan and a pre-arranged budget, the risk is to invest on many small activities that will lead nowhere.