Good for them.
It is due to introduction of "sports" appropriate for middle aged people.
I don't think curling is the best example to use when stating that athletes can compete in their later years.
Shani Davis had a rough time in 2014 and his having difficulty this year.
Shawn White is still competing and winning because he has the money to build is own facilities and train year round. That is not to say that he isn't great, but few others have that advantage. Michael Phelps has his own pool too. Even with their financial advantage, they are rare.
I was in better physical shape at 60 than at 20.
Yay old people!