The main purpose of the Eliminating Thickets to Increase Competition Act, also known as the ETHIC Act, is to simplify the patent process related to pharmaceuticals and biological products. The goal is to reduce the complexity and number of patents that can be asserted in legal actions, which can create barriers to competition and innovation in the drug market. Key provisions of the act include a limit on the number of patents that can be asserted in a legal case for patent infringement.