Re the judicial system, I don't think anyone picked up the number of convictions of subpostmasters. Remember that many of them pleaded guilty of false accounting in order to avoid a possible conviction for theft. And most judges would only have seen a handful of cases spread over a number of years.
In my view, the problem for the criminal justice system is that, since the Youth Justice and Criminal Evidence Act 1999, the courts are required to assume that computers are working correctly unless there is evidence to the contrary. This reversed the legal position - prior to this, the Police and Criminal Evidence Act 1984 required the prosecution to prove that any computer was working properly before they could use anything produced by the computer as evidence. The change came as a result of a recommendation by the Law Commission, which seems to have thoroughly misunderstood the complexity and reliability of computer systems and, it is now clear, misrepresented the views of the experts quoted in their report.
Many judges have little understanding of computers. For example, the judge in at least one Horizon case commented that any problems with the computer would be obvious to the operator - a comment that is clearly untrue. This led to judges refusing to order disclosure of material that would have helped defendants to show that Horizon was faulty and misdirecting juries. But the primary fault here lay with Post Office and its lawyers. Even if no-one else in Post Office was aware, the lawyers knew that they were required by law to disclose to defendants any evidence that might undermine the case against them and that this duty continued even after the defendant had been convicted. They nonetheless failed to disclose evidence that clearly should have been disclosed. Indeed, it there are emails in which they discuss not disclosing information simply because it might throw doubt on previous convictions.
This refusal to disclose continued through the group litigation and continues today - disclosure to the inquiry into the scandal is often late and/or incomplete. We also saw in the group litigation that Post Office repeatedly made statements that were clearly untrue. One example of this was that, for a long time, they insisted that there was a "dispute" button on Horizon that subpostmasters could press when Horizon showed a shortfall. They eventually admitted that this was a fiction - there was no dispute button and there never had been.