Right where luck is.
What seems like a "lucky break' to the casual observer is very frequently the result of years of work that allowed that person to take advantage of that moment. The moment is also frequently only clear in hindsight, and is often more of a "I heard you know about X, do you have a minute to talk to Y about X?" thing, than a "Here's a crazy promotion!" fairytale.
Or maybe you're just lucky enough that you've never been in a frame of mind to notice its absence?
I know nothing of you as an individual, but if we define "luck" as events unfolding in your life beyond your control in a positive manner it's absurd to say it doesn't exist. We are all brought into existence either lucky or unlucky, relatively speaking. Were you born healthy, attractive, tall, rich, smart, with loving parents with a stable income, in a first world country? Or were you born poor, diseased, addicted to crack, and into sex slavery?
Yes, there are things you can do to improve your lot in life, but saying luck doesn't exist is a harmful truism. You believe it because it makes you feel in control of your destiny, not because it has any basis in reality.
Tell me how you feel about luck after being diagnosed with a terminal illness that will make the rest of your life miserable and deplete the savings you pass onto your grieving loved ones.
This is the idea of "luck" when discussing "meritocracy" and people being promoted, which I think was kind of clear if you read past the first three words.
No wonder you don't believe in it if you don't think luck includes any element of randomness.
Tell that to people that were born poor or with a big disability or into an abusive family. Compare their chances and fate with those that were born into a good family with plenty of resources. What do you call the source of that difference? Most people would call it luck.
Or do people imagine that there’s a global repository of souls which are randomly drawn from when two people have reproductive sex? The contrasting idea to luck is fate. People don’t have as much of a problem with luck as they do with fate.
Also, while that extreme example is somewhat illustrative, I think for most of us it's that we're one of 20+ engineers, illustrators, business-types, etc in a department, and the "luck" we see around us is explained by what I wrote.
Luck implies unexplainable randomness. Example: The person who got the promotion was "lucky", because they just happened to have knowledge in a field that was needed. There's no luck there, they spent years learning that information.
It's not just about parents or upbringing either. Mark Zuckerberg's roommates - Hughes, Moskovitz, and Saverin - were his roommates by luck. What if they'd gone to Yale or Brown or Stanford? Or not been assigned to those rooms? You might say "But they worked hard to get into Harvard and be exposed to those opportunities!" - but so did (almost) everyone else who got into Harvard. Most of the other people from that class aren't billionaires now - they're merely highly successful professionals.
I bet you also believe the justice system is fair and that a poor Black teenager caught with weed will be treated the same as a White kid in the burbs...
People who have been born into royal families managed to bring their countries to poverty and their dynasty to an end. People winning the lotteries end up poorer than before.
There is 100% "unluck" though: getting an incurable decease cannot be turned around in a positive way