I agree with you, but there's a valid psychological reason that people don't admit to being lucky more often. It's because to maximize your chance of success you have to focus on what you can control. Sitting around and looking at others to try to dissect what was luck vs skill is a sort of armchair criticism where the practitioner is immune to failure by virtue of not even trying. Ultimately the question of luck is so subjective that it starts to become philosophical at some point. After all, so many small things happen via day-to-day serendipity that anything that actually happens can be considered incredibly lucky. On the other hand, one has a lot of agency when it comes to building a company, and the art of building a startup is about matching incredibly limited resources to the highest return activities, and ratcheting that over and over again through years of changing circumstances. All the luck in the world won't drop an Instagram-like success in your lap without just the right preparation leading up to that amazing moment.

In short, it's not that luck isn't super important, but if you are thinking about luck then you probably won't be ready to capitalize on it.

Of course luck is important. Elon Musk wouldn't be where he is today without at least some luck. On the other hand, a lot of people have had much more luck and opportunities than Musk and still didn't go nowhere. And the people with the drive and capacity of Musk who didn't get lucky are almost all still quite successful.

While luck isn't something you can completely control, it doesn't have to be entirely random either. I read this article a while back talking about a "luck surface area"[0], which you can expand, increasing your odds of being "lucky" in the future.

[0]: http://www.codusoperandi.com/posts/increasing-your-luck-surf...