It's a good point that as IoT devices proliferate there are security implications because your house will have dozens or even hundreds of devices all talking TCP/IP using whatever random protocols and implementations each device's manufacturer came up with.
That being said, I think it's unrealistic to imagine that each little company should hire their own security experts to make their own rock-solid stack, because many of these devices are home-made, or made by little startups, etc. And even if every manufacture aggressively tracked technology, users won't upgrade their firmware constantly.
Instead, I'd suggest that a better option would be to standardize the basic communications and develop a FOSS hardened communications stack for IoT devices, and push IoT producers to adopt it, so that everyone at least builds on a secure platform. There are many communications stacks for IoT, but the problem (IMO) is that they're generally proprietary by companies trying to "win" in a battle between IoT stacks, and because there are so many code bases, and they are proprietary, they can't be trusted, and even if they are trusted, they can't be used by all developers because they're tied to proprietary platforms.
So what we need is an IoT stack, secure and efficient enough to run on tiny processors (Arduino...) ideally grounded in an open standards group such as the IETF. And with a marketing program to drive all IoT platforms to adopt it. Of course, there can be multiple competing implementations as there are with all network stacks. That's valuable from a security perspective, because it prevents everyone from running one code base and thus having the same security vulnerabilities. And, of course, competition makes everything better, as they compete to be more efficient, secure, etc. As long as they are interoperable, and based on a fundamentally secure design.
Of course, this won't fix all problems - you can certainly build an insecure app on top of an secure protocol - but at least it'll eliminate a bunch of "basic" problems, like identity and securing streams, etc.