I'll admit I was late to the HTTPS party.
But post Snowden, and particularly after the result of the last election here in the US, it's clear that everything on the web should be encrypted by default.
You have an unalienable right to privacy, both in the real world and online. And without HTTPS you have zero online privacy – from anyone else on your WiFi, from your network provider, from website operators, from large companies, from the government.
The performance penalty of HTTPS is gone, in fact, HTTPS arguably performs better than HTTP on modern devices.