It is to some extent as is everything in life. Luck is enormously important. If you have been born in the slums of Calcutta, you likely wouldn't even be typing here let alone pursuing your goals. Luck.
Debussey's comments were aimed towards people living in the west.
And even if luck is important, most people having a job they truly love have done their share of introspection and experimenting to find out what they love in the first place, before working on their skills to make themselves a match for a career they want to pursue. This is a result of an attitude/belief, not luck.
No offence, but you seem to be very negative at times.
Your beliefs forms your life through dictating what actions you take and so on, and walking around with a belief that luck = the main factor won't help you much because it = a great way to avoid attaining inner locus of control and never doing what = required to actually getting a good career. This = very similar to learned helplessness
Luck favours the prepared mind, right Debussey?
You and Debussey = in 100% agreement