I successfully patented a product and licensed that patent to a small company that does quite well selling a product based on that patent. It did cost about $15

I successfully patented a product and licensed that patent to a small company that does quite well selling a product based on that patent. It did cost about $15k, but that's business risk. If a megacorp ever infringed the patent, we could sue them. Sure, they could try and work around it with other designs, but their product wouldn't work as well.