I would be genuinely interested to know how well the average wordpress blog handles a hug from the HN frontpage! :-)
Millions of sites use WP and there are configurations to mitigate this. Some caching and easy server config will be enough to survive the “hug”
WordPress handles volume just fine. Nothing a HN hug would disrupt.
WordPress is used at scale by many companies.
Better is use a static site plugin, then you don't have to bother with configuring any caching or external services.
Best is also use the SQLite Database Integration plugin, so the server doesn't even have to run MySQL/MariaDB (other than initial installation), and on an otherwise light server, the filesystem will effectively keep the site in page cache while using less memory, if I understand that correctly.
The WordPress interface can be kept behind HTTP auth or client cert.
Several WordPress caching plugins, like W3TC (https://wordpress.org/plugins/w3-total-cache/), actually add rules to your Apache/Nginx server so that the cached HTML pages are served statically without touching PHP.