@tridge @MagicRuB: clearly what's been happening here seems very crummy, but two thoughts came to mind:
1) Have you considered having an Apache style CLA on AP that would allow you to change the license if you decide it is the best course of action?
2) As I was discussing a week ago, as much as the GPLv3 is great for many uses, I am worried that any vendor of any piece of hardware that has enough potential to injure or kill others if it misbehaves, is not going to feel good about selling hardware that can be reflashed by the end user with firmware that they did not verify is safe, and for which they could be sued for millions if their hardware crashes and injures/kills others after the firmware was replaced/modified as allowed by GPLv3.
If a 50lbs drone to do crop dusting is modified by an end user, and crashes into a school, wiping out some kids in the playground, do you think the parents aren't going to sue the drone company into oblivion, or care a single second that the firmware had been modified by the end user as required by GPLv3?
I personally think if you had GPLv2 instead, or Apache2, more such companies would be willing to be using the great ardupilot codebase.
I'm sure many such companies are not against open source at all, nor do they require a BSD license, but for the reason I just explained, GPLv3 requires too much from them liability-wise.
As much as GPLv3 would be great for my Tivo or my Chromebook, or my phone, I'd be more than happy enough with GPLv2 for ardupilot since it's still just as free, and if some vendors ship ardupilot hardware that I can't reflash, I don't have to buy their hardware.
As things stand, it's what they are going to do anyway, except they won't even have to provide their source code at all, which is even worse.