All of the above.
It's the system. We get the best out of our players, even the plodders. The lazy ones and bad attitudes get moved on quickly. If you miss or turn up late to a training session, or stray from your nutrition plan that is a big deal. That is part of Ivan's culture. Every little thing makes a difference. If you don't do the hard yards someone else will and they will take your spot.
They are well coached and everyone knows their job.
Also not to be underestimated is the drive of certain players like Nathan and Yeo who want to win every year. Some players are happy with one title, others like them are not. The same mindset Lockyer and Cam Smith had. We they lose it burns them for more success. They try even harder next time. That attitude rubs off on their teammates.