Me: Instead of doing X we could do Y, that would be better.
Boss: No, bad idea we keep doing X.
a few months later
Someone external: You could do Y
Boss: That is a great idea. lets do Y.

Why does this sound soo familiar...

But Y?

I‘m glad about the fact that people can‘t hear my thoughts in such situations.
I‘d be in jail in no time.

This is what you know. You can make suggestions on things to do knowing they will get rejected. But you also know that you can perhaps make the suggestion later after it has been mulled over that might get accepted. You might need to get a sales guy or another dev to make the suggestion, but this could be used by you to make improvements. Somehow figure out how to make suggestions by proxy. Articles, external devs, other managers, etc. Or you can try making him think he thought of it in the first place.

I cannot tell you the amount of times I've got changes through, a few company wide, and every time it was by first identifying who makes decisions, and second determining who they will listen to.

And when I tell people that want something done but cant get it, that I can get it done, its always "that's impossible. They already said no."

Well, they said no to *you*.