> Unneeded efforts is where all the technology began.

let's say i grant this, but will you employ the said tech unless it is useful for you to do so?

the question here is about the purpose of going all synthetic.

1. sure, if say man can devise a way to manufacture a multitude of food "synthetically", that us just one purpose served i.e. food. you can keep replacing these various purposes that plants provide to human life. Let's say at one point all non-human species become extinct by human means or otherwise. after this we discover a purpose through their lack (even without this said discovery, it can be likely that we might not even know what we have lost, that could be or even then might have been useful to us, humans). now isn't that a tragedy? basically even if the "synthetic" means of some purposes to which other species benefit us were to be made economical somehow, that does not justify wiping them out even looking only through the lens of HUMAN benefit.

2. what is "synthetic" and how can synthetic means of achieving these purposes be made economical? first to have such an economy we would have to replicate the chemical efficiencies of photosynthesis etc. basically, copying life. second, we would need the self-replicating capacity too since this goes a long way towards economy, right? again, copying life. we might as well discover something the scale of a cell with self-replicating molecular architecture might be the way to go about it. we could as well end up making something which looks a lot like life actually and take a hell of time to achieve it, even provided we end up copying a whole lot of it (because it would be massively difficult, even this being a huge understatement, without a reference point i.e. existing life). now if all life on earth except humans if wiped out hypothetically through some means, this effort would be justified even if prone to instant failure because of our imminent deaths. but otherwise i don't see a point.

I'm not discouraging gaining knowledge about life and how it works, only that the argument of wiping it out to be replaced by everything synthetic, even someday doesn't make sense. do understand there is no such thing humans someday having all the knowledge. that day will never arrive.