There rarely is a secret formula. It's some combination of seeing something others aren't at the time, having access to resources and a good enough execution.

Having access to KFC's secret recipe isn't enough to build KFC. Similarly, Paul Graham doesn't have some big secret to safeguard.

The "secret formula" probably looks something like this:

Be rich. Be well connected. Invest wisely. Be lucky.

Know someone with a huge location in mountainview that you can use as a backup to a sf location.

You can't really recreate this kind of company anyway. What started as a unique idea has become a viable business by creating a unique set of networks and cultures. It's not really about the idea anymore, they've got capital and inertia.

Good luck copying that.

Maybe not Y Combinator as it is now. But you sure can copy the way they invested in the beginning. Not every idea YC is funding is a huge success I assume. and not every team they don't invest in will fail. So there should be a lot of opportunities there. That is where all the other accelerators step in. Given how hard it is to get seed funding in Germany the space is not yet fully occupied it seems.