It won't happen. If we reevaluate arson cases, people will push for a wide reevaluation of other convictions based on types of evidence that have been shown to be flawed. This includes hair analysis, fingerprint analysis, bite mark analysis, bullet analysis, and eyewitness accounts. Too much added work and a truth too painful to acknowledge.

Also, the criminal Justice system is notoriously confident and resilient to self examination. It's amazing what it can take to get even one person a new trial.

I think a lot of the "confidence" is taken essentially philosophically too. A lot of people who are willing to work on the prosecution side firmly believe in some type of "procedural justice", the notion that a verdict reached by properly following all legal processes, even if factually incorrect, is a just verdict. There's a big "assuming the process is fair" part of that belief, but those people don't go in thinking the process is unfair, and then also contributing to the process being unfair.

Even DNA analysis can be flawed.

While it is not perfect, the other examples have been shown to basically be fraudulent. Different levels of flawed.

DNA has been used to help free people, but even when the evidence is available it's often suppressed to get a conviction.

https://en.wikipedia.org/wiki/Innocence_Project

It still isn't perfect, and the certainty of a match has been over sold to get convictions too. It's rare, and requires intentionally misleading people, while my other examples could be wrong with everybody trying to be honest.