Without fossil records of the first life, it very well may be impossible to deduce the precise path chemical evolution traveled or exactly what the anatomy, physiology, genetics, and biochemistry of the original replicators then subject to biological evolution were, just as it may be impossible to do that for man.
You're probably wrong about that. We just won't necessarily say that it is the same organism that nature generated unaided.
That abiogenesis is a plausible explanation that is founded on facts, data, and a hypothesis that can work? The evidence is that life is here, and the alternative to abiogenesis as the explanation for the first life on earth - an intelligent designer that created the universe and the life in it - cannot be called more plausible than a possibility that requires no intelligent designer, so abiogenesis is a plausible solution to the problem.
Moreover, we see in every living thing every day how nonliving matter can be arranged into living cells without intelligent oversight. The laws of physics and chemistry are enough. All that's necessary is for the right ingredients to come into proximity, align themselves according to mass and charge distribution, and react. It's automatic.