Let's encrypt really helps get ssl everywhere. It is not super easy to set it up, but I am sure this will get better as time goes, this is huge.
As someone said, if it could work, just by saying SSL yes, it would help a lot.
Making free certificates available to hackernews readers who are already convinced of the need for encryption, are tech savy enough to implement it themselves following best practices isn't helping much to encrease encrypted traffic. These users would have used a commercial certificate anyway.
Which is why it is crucial that the client be integrated by default in the web server (apache, IIS, etc) for the target audience to use it without having to understand how it works.