This is what a 5MB hard drives looked like in 1956 (note: required a forklift)
thenextweb.com
thenextweb.com
"In September 1956 IBM launched the 305 RAMAC, the first ‘SUPER’ computer with a hard disk drive (HDD). The HDD weighed over a ton and stored 5 MB of data."
RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /index.php [L]
if you just SSH in to the server, cd over to the HTML root, wget the page in question and save the file as the name of the path, it'll statically cache it and instantly alleviate ~95% of the work needed to serve the page.
Dynamic pages are the culprit in /any/ dynamic CMS, and caching is the solution. You could use Varnish, or write/find a memcached plugin, or use redis or whatever other key/value store is trendy at the moment...it's all caching and it's the best way to make dynamic sites fast (besides Cloudflare, which is just "magical" black-box caching)
Edit: TL;DR using nginx or lighttpd or cherokee or webrick or whatever other httpd happens to be trendy this week won't help that much. Properly configuring a caching system will help an order of magnitude more.
We'll fit a lot of more data onto them, sure. But the physical size of the largest/most common hard disk available at that time is unlikely to change much.
There's 32gb of storage on my phone, held in an area roughly the size of a dime. It's not a hard disk, but it shows where hard disks are going.
Many things have shrunk: cell phones, thumb drives, wall warts, personal routers/access points, flash lights, inkjet printers…
Some things can not successfully shrink: keyboards, displays…
But there are very few things that have artificially resisted shrinking: Household telephones and credit cards come to mind.
I think hard drives are a component. 3.5" will yield to 2.5" as each drive stores enough data. Smaller platters start to have diminishing returns. Before you know it the whole product will be over run by something solid state and no one will care what the last size of buggy whip was.