Not because of steeling or use IMHO. It will be mostly because of the sheer amount of low quality open source or freeware products out there with no maintenance and people's increasing ability to generate bespoke fit for "purpose" code. I think large projects have the potential to benefit with the right gate keeping and processes.
The changes to the law / interpretation is part of the mechanisms of how the pendulum swings as the swinging is a human thing, so it happens on longer time scales. But it can definitely feel like it's over. (But each swing is different.)
Don't do this because of this, you will be a pawn being told to do something with a potentially massive cost to yourself and very little gain / loss on either side, not to mention other than the owning corporation what does source control have to do with operating systems. It doesn't send the right message of a boycott. It would hardly register on Microsoft charts.
It's borderline if it's too good to be true... I wonder about the long term stability of signal. I guess if it does disappear it does leave the protocol. However I would have wished for some means of integration between the signal compatible providers. (Perhaps it exists and I'm not aware?)
If amazon can pull of people paying for this, this opens the doors to many more companies with different philosophies producing devices, perhaps even reverse engineering the existing devices including open source. If not, e-waste.