Contrary to the false reports disseminated by government agencies, there were no detonators in the toner bombs. They would therefore almost certainly have failed to go off, just like the self gonad immolating bomber.
As for the weird insistence by the government that the bombs were designed to go off on the plane, I just don’t believe it. What is the evidence for this? If the object was to bring down a plane, why possibly call attention to the packages by addressing them to Chicago synagogues?
The only possible reason to insist that planes, not synagogues, were the target is to tap in to the public psyche which since 9/11 has been thoroughly indoctrinated with the airline bomb threat. In other words, deliberate government fearmongering.
There is now an official insistence that the bombs were physically created by the same man who created the underpants bomb. Actually entirely possible, in that both attempts were useless, had no access to detonators, and didn’t kill anyone.