2 words - Noriaki Kasai.
Yes, it's a different sport. But, ski jumping is like figure skating in that it is, generally speaking, a young person's sport. Normally, you are past it when you reach 30.
Yet Nori went to Sochi aged 41, and came home with 2 medals: a silver in the big hill individual competition, and a bronze in the big hill team competition.
And since Sochi, he has had 12 more World Cup podiums, and even won 2 of them - one on a big hill, and one on a flying hill.
Before the 2013-14 season, it had been 10 years since he won a World Cup. For the few years before it, he was really struggling. He hadn't been on the podium for 4 years, and had very few Top 10 finishes in that time either. Yet he came back with a bang.
Who is to say that Zhang Hao is not going to do the same? Go through a period of struggles, and then spring back to the top.
I know, it is unlikely. But, it is possible.
CaroLiza_fan