Thanks.
That's the problem. Mirror life may not be a problem for the biosphere in the long run but it could totally be a problem for humans in the short run.
Mirror life can only use the fats and a few amino acids of the normal life. All sugars have chirality so they would need some enzymes to east their own mirrored sugars and another set of enzymes to eat normal sugars. Also, most amino acids have chirality and they would have to reverse them or make their own.
So even if someone waste a few gazillions dollars to make mirror life, it would not be able to eat most normal food.
Until mirrored life evolves enzymes to eat non-mirrored sugars, mirrored life will be at a large disadvantage.
But with exposure to our environment, replete with non-mirrored sugars, that sets up a large evolutionary pressure in the direction of finding those enzymes, in addition to the mirrored enzymes they will already have for eating mirrored sugars.
With such evolutionary pressure, it seems plausible mirrored life will evolve those enzymes, even though non-mirrored life appears not to have done so, or at least not retained it. Because there has been no equivalent evolutionary pressure for non-mirrored life to eat mirrored sugars.
If mirrored life does evolve those enzymes, due to that asymmetric evolutionary pressure, then instead of being at a disadvantage, it might give them a temporary advantage over non-mirrored life.
Until mirrored life evolves enzymes to eat non-mirrored sugars, mirrored life will be at a large disadvantage.
But with exposure to our environment, replete with non-mirrored sugars, that sets up strong evolutionary pressure in the direction of finding those enzymes, in addition to the mirrored enzymes they will already have for eating mirrored sugars.
With such evolutionary pressure, it seems plausible mirrored life will evolve those enzymes, even though non-mirrored life appears not to have done so, or at least not retained it. Because there is no equivalent evolutionary pressure for non-mirrored life to eat mirrored sugars.
If mirrored life does evolve those enzymes, due to that asymmetric evolutionary pressure, then instead of being at a disadvantage, the ability to eat both types of sugars might give them a temporary advantage.
if it did I would have thought it would have appeared in the past 5 billion years or so
It may have appeared and been outcompeted. That doesn’t suggest its (artificial) reintroduction would again be outcompeted
Now, with L-amino life everywhere it would have an even bigger starting problem.
We see this with extremophiles: organisms which can grow in nuclear cooling ponds full extremely badly when transplanted to nutrient rich environments with other, less capable organisms.