Final answer:
Goods and services in the bottleneck quadrant of the portfolio matrix are characterized by difficulties in substitution and switching suppliers, coupled with few suppliers meeting technical or capacity needs due to specialization and scarcity.
Step-by-step explanation:
In the portfolio matrix, goods and services in the bottleneck quadrant typically have characteristics where substitution and switching suppliers is difficult, and there are few suppliers that meet the necessary technical or capacity requirements. This implies that the goods or services are somewhat specialized, often due to unique specifications or high technical standards that are not easily met by many suppliers. As a result of this scarcity and specialization, firms in this quadrant face challenges with securing supply and may have limited bargaining power. Such conditions indicate a dependency on a limited set of suppliers, making it crucial to manage these supplier relationships carefully.