Make your request easy to act on.
If there is no action from those above you on your idea, then it could be because you haven’t presented it in a way someone can act on. (It could also be because your idea sucks, btw. Just sayin’.)
I would encourage you to do two things.
First, do the initial thinking so that whatever you are presenting is clear. What is the idea? What problem does it solve? What precisely do you want? How do you envision it getting done? The larger the ask, the more time should go into getting the thinking clear.
Second, end the request with a clear next action. “Here’s what I think the next step is to get this idea implemented…”
We want to make it as easy as possible for our ideas to grow legs. Sometimes, though, the very next step is unclear. If that is the case, then workshop the next step with whoever you are meeting with before the meeting ends. “I am not sure what the next step is on this. What do you think?”
Our lives are full. Because of that, we will often shy away from helping somebody do the thinking on their initiative. It’s not because we don’t like you, it’s because there’s only so much time.
But if you make it easy enough, who knows? I might just put down something else that was harder to help move your idea along.