If the statue of limitations has not expired, then the statute of limitations has not expired. Maybe without prejudice and confidential (sometimes called "off the record") negotiations have broken down.

Would people be laughing if it had been a piece of broken glass, or if, as in the case (Donoghue -v- Stevenson) that founded the English law of negligence, a decomposing snail? Or if a parent's child had been killed by peanut allergy when a peanut turns up in "free from nuts" food?

You expect to be able to nosh fast food just like that. If you break a tooth doing so, it sometimes hurts like wossname, and you may have to lose the tooth and have a bridge or an implant or gnashers afterwards, and with the price of dentistry in the USA as reported I'm not that surprised at the total figure.