I wasn't so much saying "phew, you can relax" as I was saying "this is why you haven't seen a new Internet worm based on this concept."

It can still, of course, be done in one-off scenarios (attacking a peer on a guest wi-fi network is one easy possibility) but it's not Heartbleed-level scary, because you can't just "scan the Internet" for the vulnerability, and attack every vulnerable thing you find to useful result.