It's a product, not a subscription, so there aren't renewal terms. The user cancelled automatic renewals through PayPal, but it should still be possible to renew manually.
I just turned off option "Allow users to purchase more than one?" under Store Settings for the product, and it's now possible to purchase/renew. This would allow a user to purchase two simultaneous memberships, which isn't appropriate, but perhaps that's better than prohibiting renewals.
It seems that the system isn't clearing a flag when a product expires.