The “machinery” being the marketing, distribution, and general scale, not the physical vats used to mix it.
Even if you could replicate the exact flavor, you’d still need to do it at scale and get it into stores and convince people to buy it.
As to “just make it yourself”, everyone can make a sandwich, Jersey Mike’s and several other sandwich shops exist successfully.
I don't know if you have seen it, but the recipe is 1:1 of what cocacola is, scientifically proven. (Altho it tastes closer to original cola since replicating coca 1:1 is impossible)