My very favorite examples are in the airline industry. Twenty years ago, Continental Airlines boasted of the simplicity of its fleet of planes. One benefit of this plan was having to carry fewer spare parts. But there wasn't much flexibility for matching equipment with the specific needs of a route. Today, most airlines have a variety of aircraft.
More aircraft types means more complexity, but greater flexibility.
There is a trade-off here. Competition forces enterprises to lower prices, add features to products and services and treat customers with great specificity. Product differentiation often yields more types of products and more complexity. However, it often requires us to treat each customer with a uniqueness that makes the customer happy, but inherently complicates the business model. Customers usually want to be treated in a unique way, catering to their special needs.