Is Lean a 'common sense' way of acting?

In my opinion, not at all.
Lean is very often simple, but not (always) intuitive.
If it were intuitive, it would be so easy to implement, earlier than it has been and used more widely.
And would be immediately and easily sustainable.

But it hasn't been.
Why?

Because lean thinking call for habit and discipline. Lean is kata, a kind of behavior.

But it's also (and this is in my opinion its core value) logic.

The basic idea is shocking and striking, but after  the first tremendous flash of lightning, we must unlearn almost everything we knew and rethink business processes from that new perspective.

And from then on, continually improve. Hardwork.