" we do have the ability to synthesize billions of base pairs" This is a valid point. We don't have the technology yet. There was once an SBIR opening for long DNA synthesis but I did not keep track of it. But, given we have the technology it still would not be enough. To slowly make an elephant a mammoth. Yes. Maybe. But making a Tyrannosaurus Rex from scratch is tricky, you also need cells, mitochondria, DNA methylation etc.