China was a huge country with abundant resources, and its population had already reached tens of billions. Thanks to its large population, it had a steady flow of geniuses, albeit not an endless one.
However, thunder geniuses were considered rare among the many geniuses. Although humans had mutated due to spirit energy, most of the changes had affected the physical body. People who could control elements or had abnormal abilities were relatively rare. There were also very few thunder geniuses amongst those who could control the elements.
The same was true for those with the recovery ability.
Of course, despite their rarity, China had a considerable number of such geniuses due to its large population.
Logically, when there were that many geniuses, there would always be someone who had achieved what Lin Yao had. Lin Yao's advancement was not considered that big of a deal.