How big a part does luck play into getting rich?

You may be interested to read the book "fooled by randomness" which is a book about luck determining whether you become rich unless you are a dentist.

We tends to call the unknown factor that make things work = A stroke of Luck

I think hard work lays foundation and many times just need the right equity, the right market, right people , right timing.

So long as we lay the foundation , do the hard work (because even win lottery also need the work and $ to go buy ticket) , reward will comes (not lottery 😜)

As it comes at time we expect it (we call it reward). When not expected, so we call it Luck.