Shadowing may get you the same experience, but it will not make you The Person Who Solves Problems in the eyes of others and thus won't help your promotion. Which was the author's point.
That doesn't get you promotions either. It just makes you the go-to person for everyone to sort their stuff out.
If you want a promotion, move companies - it's a safer bet.
That depends on the company. In terms of reputation/respect, I earned most of it when my boss was on vacation and I had to make decisions and take responsibility. Didn't benefit me in that particular case, since our company was bought by a bigger one and they started calling the shots, and then I left that job. So I suppose I should upvote you :)