I'm not sure about all world record holders, but Feliks Zemdegs uses the Fridrich method.
How many algorithms someone uses doesn't always influence how fast that person is. With the Fridrich method, there are 41 for F2L, 57 for OLL, and 21 for PLL. However, you don't need to use all of them to be a fast solver. Practicing solving the cube is an important part of what allows people to be really good.