Epic didn't remove IAP... they advertised a lower price elsewhere, which is against guidelines (which is not a contract), and did so via an unreviewed update.
Note that updates via webview or JS code are explicitly allowed by contracts, and what Fortnite did is very likely to have used that mechanism.
Note that updates via webview or JS code are explicitly allowed by contracts, and what Fortnite did is very likely to have used that mechanism.