Completely incorrect claim, the IoT industry doesn't spend a penny on security, and therefore will be vulnerable to these type of attacks. If anything this is proof that the security industry does work, these attacks are happening on devices where there is no security budget - not on servers with large investments in security.
How many pennies would've been needed to insert a simple page forcing you to change user/password combo and to choose a reasonably strong password after first boot ? In the case of Mirai it's not even a cost issue, just lacking good practices.
Until there are regulations in place to make them do this, they will not care.