The Internet is a monoculture, with roughly 40% of all web sites now depending on a single, openish-source blogging platform called WordPress.
There are roughly as many WordPress sites as there are people living in North America.
Needless to say, digital monocultures are undesirable. A single programming error can instantly render millions of web sites — and sometimes even their readers' computers — vulnerable to attack.
In regards to WordPress, the situation is particularly bad because WordPress isn't just WordPress; it's a massive ecosystem comprising hundreds of thousands of third-party themes and plugins, some of which require indefinite subscription payments to keep the updates (and any fixes) flowing.
Automattic, WP's parent company, is well aware of the situation, but rather than take any steps whatsoever to protect end users, they've chosen to turn basic vulnerability awareness into a subscription side business instead.
Long story short, we're all doomed.