*sigh* it will have an effect, on people that rely only on Google or Microsoft, yes those people would be affected, but email in of itself wouldn't.

in fact I'd love for that to happen, it would make email open again; email has been controlled by powerhungry maniacs for years now all because google offered 1 GB of data in exchange for your privacy. The advent of gmail was literally one of the things that exponentially increased the speed of our descent into the surveillance dystopia we find ourselves in now. 

 I don't disagree with Gmail being a major culprit. 

Maybe I'm catastrophizing, but given the interconnected nature of the economy, infrastructure, and livelihoods, I would think such a move would be more than the mere inconvenience of having to switch to protonmail or something.

There would be big ripple effects that do real damage.

Maybe that level of pain is inescapable if we want to tear free of the surveillance state. But it makes for a pretty effective lever of influence in the meantime.