Nobody actually would argue with the challenge regarding IoT and security. There are plenty of examples out there proving how easy it is to compromise devices connected to the Internet, especially as security is really not at the forefront of companies developing these devices.
We often talk about the impact this development could have when it comes to the critical infrastructure or if these devices become part of a larger botnet. The user will never realize that he/she is part of it (nor will they care) but the impact is huge.
This has been show just recently: He have seen a DDoS against KrebsOnSecurity with a power never experienced before and at the root of this were devices like Webcams being compromised.
This is a huge challenge for the industry as it shows the overall vulnerability which comes currently as a price for digitalization and SmartHomes/Cities/Cars etc.
Besides the overall call to write better software, I do not see a silver bullet at the horizon, yet.