Starbucks is offering coffee in lots of different sizes and flavors. Obviously this business model is doomed out of the following reasons:
1.) First and foremost the production of coffee at Starbucks has a higher complexity than in a shop which only produce one flavor. A business model which makes coffee harder to make, can only fail as the producers of coffee make the final decision about the success of a product.
2.) Customer only want one sized coffee with exactly the same flavor. Offering different flavors and even different sizes confuses the customers, especially as they all have to handle their coffee differently.
If Starbucks does not start controlling this fragmentation mess, it is destined to fail very soon.
Other companies are also doing it also wrong. BMW, Porsche, Honda, Nike, etc. They also offer variation of their products which drives the customer mad. Just image how a person need to handle different sized cars differently. Even the radio in the cars is not standardized. Customers hate this concept. In the past Ford had only one type of car the T-Model (1908 und 1928) and customer really want this today also.
The only product which follows the correct strategy is the iPhone. One phone for everyone. Apple did figure it out. Others will follow or fail.