95% of all criminal cases in the US are Plead out largely because the defendant can not afford competent legal representation
This is why all kinds of questionable investigative tactics are still used even some that have clearly been ruled unconstitutional, they know most of the time it will not matter, they just need to get enough to make an arrest, the system will destroy the person anyway no conviction needed, and most likely the person will plead guilty even if innocent just to make the abuse stop
If evidence is obviously (or with high chance) disputable, then it puts pressure even in those cases where the attorney recommends the defendant to eventually plead.
Or maybe the attorneys available to those who can't afford are just crap in general?
In theory yes, but in most cases that will be a overworked lawyer that has 100's or 1000's of other active cases, and will not spend time other than negotiation the best deal.
Even if you happen to get a good public defender that has the ability to devote lots of time to your individual case, they would have no budget to hire an expert witness to present the vulnerabilities in the Cell-bright software to a jury
Your best bet would be if the ACLU or EFF took an interest in your case, but they take on very few cases relatively speaking and tend to focus on precedent setting cases, or cases that have high public interest (or can be made to have high public interest)
>Or maybe the attorneys available to those who can't afford are just crap in general?
In some cases they are incompetent, however in most cases they are just underfunded and massively over worked. In most jurisdictions the public defenders office is funded is 1/10 or less of what the prosecutors office is funded at.
Consider https://www.securityweek.com/forensics-tool-flaw-allows-hack.... Have any cases been thrown out? I don't think so.
The defense lawyers have to read it, and the people in law enforcement need to read the cases where judges throw out Cellebrite evidence based on that.