Luck does play a part.
However i do know people who create some of their own good and bad luck. Obviously not always.
I know someone who people think are lucky. But they look for every opportunity. The progressed quickly at work. Because they used to go looking for opportunities to help other departments. They talked to eveyone and made sure everyone knew who they were. It helped when they got to interviews for promotions.
I know people who are refuse to help anyone as its not in their job description, keep themseleves to themselves etc thrn wonder why people arent banging on their door to promote them.
At work 5 of us started on the same day. My salary package was £x per year plus a parking space. As was the others. 6 weeks in, i still didnt have a parking space. I tild my director if i was not getting a parking space i expected my salary to go up until it i got it as i was not getting the full pavkage offered. I got a parking space 2 days later. Someone else didnt and complained that i was lucky. It wasnt luck and i pointed out that i put a good case together and got mine. It wasnt luck. I went after what i was entitled to.
However i was lucky. I was lucky my, now, director attended my interview and assesment day and recognised something in me and asked me to go for a different job. Its a job i havent done before, i am having studying and really out of my comfort zone. But i jumped at the chance even though it was scary. Loads have told me they would not have taken it. But i did and its veen amazing for my finances and career. It was risk and i took it. But no denying luck was involved.
So yes luck was involved but it wasnt all luck.
The same in relationships. You need some luck to meet the right person. But its not going to happen if you stay in all the time and dont make any effort to meet people or socialise.
I dont think anything is all luck. But its not all just hard work either.