In 2009-10, the New Jersey Devils were confident that 25-year-old Zach Parise would help define their next decade in the NHL. Ditto the Washington Capitals, and their 25-year-old, 40-goal scorer Alex Semin. The Columbus Blue Jackets had a 25-year-old franchise player for the next decade in Rick Nash, having signed him to an eight-year contract the previous summer.
Three years into the next decade, all three were playing for different teams.
A lot can happen in the span of 10 seasons. (Heck, two teams that played last season didn't even exist in 2009 -- three, if you count the Phoenix Coyotes.