This is really possible. There isn’t very much platinum on Earth, and there’s a lot of evidence that the vast majority of it came from meteorite hits. Incredibly, they can tell which asteroid that certain meteors came from. Platinum and iridium aren’t just “good looking”, they are incredibly useful industrially. We could use more, yesterday.
True enough, the heavy metals are made in stars. At least one family of asteroids is made up of around 70% iron whereas the earth’s crust is only around 15%.
The fact is that true space exploration won’t begin till mining and manufacturing in space begin. Trillionaires will be made and that’s a hell of an incentive.