How can someone break into the motorsports marketing industry without a specific degree?

Donate your time and become an intern. Offer to sweep floors and do whatever is needed just to be in and around the teams and brands you're passionate about. Don't focus on what you'll get paid - focus on gaining experience, knowledge, and relationships. Taking every call and every meeting is crucial because you never know what opportunities will arise. The people who succeed in this industry got there through passion and relationship-building over years, not through formal education alone. This hands-on experience will teach you more than any degree program.