Someone once asked...
Someone answered with kindness...
Yes, luck is a huge part of life, your ability to realize an ambitious goal depends on much more than your own efforts.
Another soul answered...
Depends on how you define success. You can choose your own aims to pursue and succeed at. Often times external conditions are a factor, but can be changed or mitigated. Much of Buddhism is about learning to find peace or happiness that does not depend on external conditions.