Full Answer

The root cause is WordPress's minimal approach to structured data. Out of the box, WordPress outputs a basic Article or WebPage schema object — enough to tell search engines a page exists, but nowhere near the detail AI engines parse when deciding what to cite. Properties like offers, aggregateRating, and availability are absent from default WooCommerce product pages, which means AI shopping agents have nothing meaningful to index.

Plugin conflicts are the second major failure point. When a theme already outputs JSON-LD and a site owner installs an SEO plugin, the result is often duplicate schema blocks for the same entity. Google's structured data guidelines treat duplicate markup as a validation error — and AI engines are even less forgiving, typically discarding the page's schema entirely rather than reconciling conflicting signals (Google Search Central, 2026).

Deprecated properties compound the problem. Schema.org evolves, and properties like older BlogPosting formats are quietly dropped from rich result eligibility. Sites running outdated themes continue emitting these types without any warning.

Translation: your schema looks fine to you, but every AI engine reading it sees broken data. The fix starts with running Google's Rich Results Test against every template — not individual pages. Fix the template, and every page it generates inherits clean markup. For a deeper look at how schema gaps block AI visibility, see Why 78% of WordPress Sites Fail Schema Validation.