Systems thinking or People over Process

A topic I still haven't reconciled in my study of management theory is whether systems are 95% of the success or failure of a process (Deming) or whether it's People over Process (Agile Manifesto.)

Of course it's neither, and that both systems and people matter, but I haven't squared away the dichotomy into an easily managed aphorism yet.

Perhaps "systems that enable people" are they key. Or perhaps it's "systems that facilitate collaboration."

There is no doubting that systems play an important part in getting things done. But in what ways to systems and people interaction find the optimal balance. And what is the model illustrating the point?