I think the main mistake with this is that the concept of a "complex machine" has no meaning.

A “machine” is precisely what eliminates complexity by design. "People are complex machines" already has no meaning and then adding just and really doesn't make the statement more meaningful it makes it even more confused and meaningless.

The older I get the more obvious it becomes the idea of a "thinking machine" is a meaningless absurdity.

What we really think we want is a type of synthetic biological thinking organism that somehow still inherits the useful properties of a machine. If we say it that way though the absurdity is obvious and no one alive reading this will ever witness anything like that. Then we wouldn't be able to pretend we live at some special time in history that gets to see the birth of this new organism.

I think we are talking past each other a bit, probably because we have been exposed to different sets of information on a very complicated and diverse topic.

Have you ever explored the visual simulations of what goes on inside a cell or in protein interactions?

For example what happens inside a cell leading up to mitosis?

https://m.youtube.com/user/RCSBProteinDataBank

Is a pretty cool resource, I recommend the shorter videos of the visual simulations.

This category of perspective is critical to the point I was making. Another might be the meaning / definition of complexity, which I don't think is well understood yet and might be the crux. For me to say "the difference between life and what we call machines is just complexity" would require the same understanding of "complexity" to have shared meaning.

I'm not exactly sure what complexity is, and I'm not sure anyone does yet, but the closest I feel I've come is maybe integrated information theory, and some loose concept of functional information density.

So while it probably seemed like I was making a shallow case at a surface level, I was actually trying to convey that when one digs into science at all levels of abstraction, the differences between life and machines seem to fall more on a spectrum.