You just need to know the right people in the right industries. Licensing your product is alot easier than selling it. you don't have to worry about the sales as much
If you're starting your own business hiring marketers with the right connections is very expensive (usually >100k/year) and those are the people that are going to get your invention into other companies' hands to apply to their products, which can be very profitable when you're looking at multinational corporations.