That's when you need an advocate in upper management. You aren't going to get shit for funding even if your PM is well liked and your product idea is well thought out and solid. Someone in the circle of the one who signs the checks needs to be able to talk about your product like it's the next best thing. They also need to have the connections with their counterpart at the customer's offices to be able to sell the idea to their boss, "I've heard that company X is working on some new development for Y. If we invest, we could get first dibs on using it in our flagship product." Good ideas need to flow up to be given money. Likewise, Ideas that flow down almost always end up being a boondoggle, "Let's make a box that does X, Y, and Z, get the engineers on that right now!". If your good idea doesn't have an advocate, it will die on the vine and someone else will do it instead. What's the point of spending a bunch of money investing in an idea when a competitor got customers to invest in R&D for the same idea for free? Unfortunately, your advocate is probably not going to be a technical person. They won't understand the bits and bytes that make it novel, they need a soundbite that they can easily regurgitate ("We can shrink the current production design to draw X% less resources for the same or less money.")
You could be the smartest guy at the company, have the most well rounded team, have a PM that orchestrates people like a symphony conductor, and have a huge idea that would make absolute bank for the company but your idea won't matter for shit if you can't sell it.