The bargaining power of buyers and bargaining power of suppliers are relevant, but the bargaining power of employees is not one of the Five Forces.

Supply and demand determines short-term profitability.

Entry barriers should be considered, not exit barriers.

The rivalry among competitors should be considered, not the rivalry among suppliers.

Industry structure determines long-term profitability.

The threat of product substitution is driven by availability, prices, and cost of switching to other products in addition to the inclination of the buyer to switch.

Porter’s five competitive forces are the threat of new entrants, the threat of substitutes, bargaining power of suppliers, bargaining power of customers, and the rivalry among existing competitors.

An increase in demand for widgets is likely to boost profits in the short run, but could attract new competitors. The same can be said for new products that create a wider market for widgets. However, the creation of a widget-makers’ coalition could change the balance of power in the market. One of Porter’s five forces is the bargaining power of suppliers. A coalition that brokers all widget deals could skew the field in favor of producers, raising widget prices and the profits of companies that make them.