Between companies providing the ability to cheaply synthesize DNA in bulk (Twist), companies essentially doing machine-guided evolution on bacteria (Zymergen), synthetic therapeutic circuitry (Cell Design Labs), and a host of brand new entrants to the synthetic biology space, we've a lot more capability than we did just a few years ago.
We've found enough stones that we're now starting to build our own primitive (3D, atomically precise, wet, self-replicating nanotechnology) tools. CARs, SynNotch, HBB[T87Q] are all creative upgrades to existing biological systems used where our own bodies have failed, and all only very recently effectively delivered. And we can achieve those pragmatic wins without having a complete and thorough understanding of the entire system.
This includes chemical transport, energy transfer, system construction, chemical processing and purification, adverse chemical reduction and removal, etc.
The more I look at the information obtained about biological cells and their operation the more it becomes obvious that certain popular models related to biological systems are in the category of "the emperor has no clothes" ideas.
Biological systems are so complex and so integrated and so coordinated that we still have so little actual knowledge on how and why they work the way they do. So duplicating the various industrial processes that occur within a cell with any finesse is still a long, long way off.