Why is it so difficult to build culture and convince people?

Why is it so difficult to build culture?

Why is it so difficult to convince people of something you know that works?

I often see people struggling with things I've struggled with ten years before but I still can't get them with the correct mindset or see a change in attitude.

It looks like people enjoy experiencing failure on their own only to get to the same conclusions you've been advising before.

What's your experience on building culture? What are your main struggles? What is effective?