Why is it a mistake? If you have not modified the code, then the source code is available via the same place they received it. It sounds like you just want anyone using the code to automatically become a mirror
It is a mistake for the intent of GPL licenses because if the place they received it closes down it can become difficult to get the source / de facto closed source.
The solution to this is for every place using the software to become a mirror or otherwise allow access to the source code in the same way as if they were distributing GPL binaries, correct.
> It is a mistake for the intent of GPL licenses because if the place they received it closes down it can become difficult to get the source / de facto closed source.
Are there any examples of AGPLv3 software that has become de facto closed because the original vendor no longer distributes it and nobody else distributes their copy?
Sounds like a made up problem, theoretically possible but so unlikely as to not be an earnest and genuine concern.
The solution to this is for every place using the software to become a mirror or otherwise allow access to the source code in the same way as if they were distributing GPL binaries, correct.