I think that the invention of Let’s Encrypt is underrated. I don’t have numbers, but I can guess that it amounted to an increase in knowledge sharing on the web because of its free, easy to use certificates. If not that – at least definitely made setting up blogs and static pages way cheaper.
I highly recommend giving a listen to this episode of The Changeling (one of my favourite podcasts), about Let’s Encrypt. Affordable and easy to set up encryption is big. One of the biggest things to happen to the internet in the past 10 years.