Why other people would not purchase coca cola product?

Why other people would not purchase coca cola product?
in respect to the question, in a perfectly competitive market, where their are many buyers and many sellers and in which the forces(demand and suppy) in the market determine the price.there are some factors that enhances some people not to purchase coca cola. this factors are;(1) Avalability of substitutes goods. (2) Habit: some people are so adamant in consuming a product, no matter how fall in price of coca cola they will not still buy it. (3) change in Income: fall in the income of coca cola consumer, may reduce d sales of coke. with this i believe it is clearly stated.