Why should you care?

Obviously, it matters to ME if someone steals my ideas and I don't get paid for them and don't get credit for them because it harms my earnings and my professional reputation. But why should YOU care if other people steal my ideas?

1. If they will steal my ideas and my work, they will steal yours, so you shouldn't trust them.
2. Their work is probably a cheap knock off of the idea. It will most likely be a bastardized piece of garbage and the person who came up with the idea likely would do something better.
3. If you like it anyway and want MORE quality ideas, hiring the person who stole the idea won't get you what you are looking for.

And people with power KNOW that, a la this movie scene:

There's also a wonderful anecdote about Vera Rubin, the Mother of Dark Matter, going and giving a talk with a toddler on her hip to prevent some man from taking credit for her work. You could read more about her if that grabs you.