While I agree, there's a reason that file sharing and video sites have been slow to take up HTTPS, and that's that it removes the ability for any intermediaries

While I agree, there's a reason that file sharing and video sites have been slow to take up HTTPS, and that's that it removes the ability for any intermediaries to cache the content. It puts more of a burden on ISPs and services to carry the extra load, whether it be through SSL-terminated peering, or more scaling at the home servers. It may be a necessary burden, but still, it's a pretty significant one. In extreme cases, think of the infrastructure cost of streaming say, a world cup final game over HTTP vs HTTPS.