Ivo Karlovic’s Survival and the Key to Aging in Men’s Tennis

I wonder why the top players in tennis (Federer, Nadal, Williams) are lasting longer than is traditionally the case?

- Better nutrition and recovery than previous generations?

- Unusually dominant top players, resulting in easier matches and less wear?

- Playing styles that result in less wear and tear?

- Upcoming generation not as good, so not challenging them?