When the structure of the Internet network was created, a capacity of 4.3 billion connections was expected. At present, half of them are already used and demand grows almost exponentially. Therefore, if an enormous amount is not used, the capacity of the network will be exceeded for five years.
Keep in mind that if the home automation is launched and becomes normal, many appliances will have Internet connection. With mobile phones you can already access the Internet and this type of use is expected to increase. Therefore, the question ends the IP addresses.
And then what? One of the options would be to create a parallel system that allows the connection between both systems. However, this would be a change in the hardware and software currently used, which would “be as difficult as changing wings in a plane’s flight.”