Keep in mind that "big companies" consist of many "small people". If you offer them the IP for sale any decision-maker in the company that could approve paying

Keep in mind that "big companies" consist of many "small people". If you offer them the IP for sale any decision-maker in the company that could approve paying for it will need to ask themselves: "How much would this help my career in this company personally? Or does it put me in risk of possible failure? Does it put me in competition with our other departments? How much would we need to invest our own time and efforts to integrate this IP into our product-line?".