Why consistency in product development is required?

Product management is a vast field where there are no rules. If the company is banking on certain product which has manged to hook consumers since long, then buying behavior is characterized by 'habit buying'. While in case of technology or other products where innovation and creativity drives the market , the buying behavior is driven by market challengers and leaders.

So consistency in quality has to be maintained for brand portfolio management but attributes need not be consistent. Market unpredictability has made evne the brand associated with long term connections with generations of consumers to alter their product line for sake of competition and innovation even in fmcg sector. Kellogg is a good example of same.