The Irony
Stanford — whose graduates built Stripe, Netflix, and LinkedIn — runs its own website on WordPress. Harvard runs WordPress too. These universities teach React and Next.js in their CS programs. Their graduates go to companies that run modern stacks. But the universities themselves never revisited the decision.
The Gap
University IT departments and CS departments operate in different worlds. The CS department teaches students to build on Astro and Next.js. The IT department maintains the university website on WordPress because it was the standard when the site was last redesigned. The institution that creates modern web developers can't modernize its own website.