Comment by OkayPhysicist

Without HTTPS, every link in the chain between me and your website is a potential attack vector. Maybe I trust my ISP, but do I trust my buddy's cheapo router? What about the shadowy cabal that offers airport wifi?

With static webpages, the concern isn't someone snooping in on what I'm reading. It's someone injecting content, probably malware, into the page. Let's say I have a zero-click exploit for Chrome. What can I do with it? If I just stick it on a page I control, best I can hope for is spamming it all over the web and hoping someone clicks on it. Probably not a lot of impact before it gets patched. If instead, I can wait until some router firmware gets pwned, or an ISP, I can do a mass attack where I make all the vulnerable routers inject my exploit into all non-HTTPS web requests. Much greater exposure.