That is a really good point 
Race results are a great way to add visibility and a positive success story for your team/sponsors but I would be surprised if winning local amateur bike races is a game changer for any local businesses that might sponsor riders or a team.
Nobody has to sponsor bike racing and it isn’t like there is a pool of money out there that you can command a share of by your sheer watts/kg. Focusing on what you provide to sponsors and delivering value is what will get you financial and in-kind support for your racing.
There are a lot of good points raised here about being respectful/respected in the local scene and having a strong social media presence. Volunteer work at races, leading clinics, hosting group rides that are open to all members of the community are some of the things that I see teams around here doing.
Sponsorships make sense in the context of a team and I am fortunate to be part of an organization with some really good support. But nobody is handing out top shelf race bikes and it takes a lot of work on the team side to earn the sponsorship. If your main goal is free stuff, you are barking up the wrong tree. Creating an organization that is able to support riders/races in your local scene and (hopefully) break even at the end of the year is a pretty significant accomplishment for amateur racing at the local or regional level.