At the end of the 2015 season, Rory was 26 with 4 majors and 6 other top-10. Jordan Speith was 22 and coming off a year where he went 1-1-4-2 in the majors and then finished T2 at the Masters the next year. Those two have won two majors since. Rory's been much closer (21 top-10's before today in 10 years) than Speith (7 top 10's in the last 7 years) but man it seemed like those two were going to dominate golf for a decade. No idea what happened to Speith since I only pay attention to the majors.