We know much more about biology than we used to. Incomparably more. But what we know is still very little.
Replacing foods consumed for thousands of years with foods dreamed up in a lab is a fool's errand. We've already seen continual (and ONGOING) health disasters from industrialized foods.
On top of that, there's likely already a lot wrong even with "scientifically"-enhanced modern agriculture that's not processed (animal feed, monocultured crops, pesticide use, topsoil depletion etc. etc.)
We need to stop what we're doing and actually work with the ecologies we have to produce enough food for everyone. I suspect this latest push has a lot more to do with big capital players wanting to centralize food production and remove the dependencies on unpredictable inputs (animals) than any wide-eyed dream about saving the planet.