> There's no more good reason not to have HTTPS
Cost. Today I host my website for 6 cents a month as a static page on Amazon S3.
To go https, I'd have to first acquire a certificate (lucky that can be free and with Let's Encrypt will be). Then I have to find someone to host that certificate. I can pay someone hundreds to thousands of dollars in setup and monthly fees.
Or, the cheapest option I've found is to get a $6/mo VPS as a frontend, put nginx on it, and put my cert there. The problem is that costs 100 times as much as what I pay now, and I have to maintain a server and it's not served from multiple redundant servers like my site is now.
Or I can use Amazon's free SNI support, making it so that older browsers can't see my site and I have no way of blocking people from using http or redirecting them.
There is currently no good, cheap option to do SSL only that is viewable by everyone.
That's why I haven't switched yet.