There is definitely an element of 'luck', 'destiny' whatever, that sometimes puts us in the "right place at the right time" ... I know that has happened to me more than once in my career ... but it IS all three and one more HARD WORK ...
LUCK may put us in a particular place where someone 'out of the blue' hears us and books us for a future gig(s), but it is the PERSISTENCE and HARD WORK in developing our TALENTS that gets the gigs ...
JMHO
PS: ... good attitude and energy are ALWAYS necessary ...