This will be a controversial answer for some reasons I think are misplaced. In my opinion Elon Musk seems like he has a potent toxic side to his personality, and he doesn't seem to have a very good grasp of certain things. He also legitimately seems delusional at times.

However in terms of bringing awareness, optimism, and a willingness to actively work on engineering solutions to long-term existential threats to humanity I think his impact on our culture is often understated.

If someone has a historical record of making delusions become reality, then I think they aren't really delusional.

Mr Musk's company SpaceX has brought down the cost to orbit by a factor of three. That's a big deal. Not as big as Edward Jenner & Louis Pasteur (vaccines) or Isaac Newton, but still pretty big.

Positive and delusional are different things.

It can be a fine line.