From Mahayana perspective:
"We are all one" is a simplified step in the right direction - but ultimately is not true. It can be used as a stepping stone from the mainstream primitive materialism, but must be transcended eventually.
In Mahayana we recognize that things are interconnected and interrelated. In this sense, yes, every thing (implicitly) has (hidden relationships with) all other things in it, including sentient beings, so in this sense "we" (sentient beings) are "one" (interconnected).
This non-dual perspective is a lot more virtuous than the usual worldly ethics based on the materialistic assumptions like "Winner takes all", "Man vs nature" etc. It leads to more harmonious relationships through greater awareness of the big picture. It reduces the risk of Tragedy of the commons.
However, and my Zen Master was exceedingly clear about it, even this perspective must be transcended ("get over it!") on the way to complete Enlightenment.
This is because, at the end of the day, self-identifying with "All" is still a prison. It's a very tightly controlled prison too - where everything works strictly in accordance with the Law. As you yourself said "same driver driving all the cars at the same time in present, past and future".
Instead, what Buddhism proposes (and Mahayana is very vocal about it) is freedom of perspective, or freedom from all fixed positions. This means getting rid of attachment to concepts like "I am a sentient being" or "We are sentient beings" or "We are this Universe" etc. and even transcending the concepts like "Mind", "Matter" and "Universe".
At the end, there is understanding of how things work, without putting it into any dualistic boxes and without thinking that "You" are that or any part of that.
As my Zen Master used to say:
From the perspective of All, "God bless you" - but from the perspective of Enlightenment: you bless God.
Meaning, when you're out of the cosmic prison, you're free to choose your perspective, you "got over" the non-dualism, you got over "you", and even got over "Enlightenment" and "Nirvana". As the Buddha character says in my novel:
There is an infinite number of ways to see reality, each valid from its own side, each incompatible with the others, but each having its own internally consistent logic. Every one of these different views leads to corresponding decisions, corresponding actions, and corresponding results. You must decide for yourself what to believe in and how to see the world. Do not let anyone force their judgements on you, however rational and experience-based they might seem. Do not assume anything to be obvious and not requiring critical consideration - even your own thoughts! This is because, having assumed a thought, you pick your path and not only yours.
You can choose to think thoughts that would bring suffering to both yourself and to others. Or, you can choose to look at things in a way that brings peace. However, there is no single point of view that would fit to all situations in life. Point of view is like a tool - there's right tool for each job.
Remember: by picking your point of view, you change your future. Not just your own, the future of the entire world depends on your choice of perspective. Choose your reality well!