First, i didn’t say it was impossible to evolve hollow bones. However, there is probably many more ways than one (specific genetic sequences) to get you there. Second, the penguin limb than had to adapt to flight and we know for certain there are more than one way for that to happen, But even if it did evolve flight feathers and all the other necessary adaptations, the likelihood that It would occur precisely the same way genetically is less than once in 4 billion years of history. So yes, it’s an exceedingly small chance.
I don’t see the point of your argument, other than for argument sake. Surely you are not this dense.