Why does it have to be technology versus nature? Why can't I support advancement of technology and better treatment of animals? Why can't I support more efficiency so we don't have to invade nature to get our resources?
Heck, coexisting with nature could mean entirely separating ourselves from it through technology so we don't hurt it. That's not what I want, but this is far more complex than choosing technology or nature. I'd like to choose both.
For the purposes of this argument, let's assume "nature" refers to life forms excluding humans.
Even at perfect efficiency and 100% recycling with no waste, 1g of iron will never be any more than that. Efficiency has a hard cap. If you want to expand, you need more resources. Efficiency is all well and fine, but more is going to be needed.
Technology = fast, Nature = slow. Even under ideal conditions, nature will still move only so fast on it's own. We are a notable exception. Not only does nature develop more slowly, but it will reach it's theoretical limit far before our technology does, and it will just end up holding us back. So you have to ask yourself, "At what point is it not worth saving anymore?". How much does it have to get in the way of our own development before enough is enough? The vast majority of people aren't content with developmental stasis, otherwise we would still be living in straw huts and dying at the age of 40.
In order for them to mesh like you want, we would basically just be building around nature. People don't like it when nature "gets in the way", if it can be avoided. Plus, to protect nature means spending resources on it, or just isolating ourselves from those resources in the first place, hurting our development.
To live totally separately (or as much as possible anyways) means isolating ourselves from a vast number of resources, grinding our development to a near halt.
This is why I suggested bioengineering as an alternative. While not strictly "natural", it would still allow for various plants and critters which have developed alongside us.
In short, we
can live alongside unmodified nature, but it comes at a steep price.