Maybe you can discuss follow through in your retros and come up with a plan to increase that sense of ownership from the bottom up :) I know depending on your org that isn't always possible, but it's an idea!
I make great efforts to make sure we follow through on action items on my team, and strong top level support has indeed transformed our entire organization and consistently makes Plaid a better place to work. Retrospectives without follow through can become very frustrating that's why action items and owners are a key component.