Strategies to reduce the threat of substitutes
1. Businesses can make it expensive or difficult for customers to switch to a substitute (although they have to be careful not to annoy them)
2. Customers are often loyal to a brand that they perceive as better. If companies can differentiate their product and create brand loyalty, they'll reduce the threat of substitutes
3. Businesses can identify a group of customers whose needs aren't quite being met and market a product designed to meet their needs exactly, eg, environmentally-conscious disposable nappy users. There won't be any substitutes for them to buy (until other businesses notice anyway)