Internet of things is a thing. I've been following the subject of IoT for some time. In the beginning It didn't really look like a thing to me either and that's perhaps because just few months ago it didn't have enough of a shape to call it a thing or I just didn't know enough about it.
In my books, I call something technology if it comprises of set of problems and solutions to those problems. Here's what IoT problems (and solutions) are:
1) Measuring values in physical world and sometimes changing physical world as response to commands (sensors and actuators)
2) Transporting measurements to computing centers where they can be analysed and acted upon (wired and wireless communication hardware and protocols)
3) Power independence for measuring devices (hardware that consumes low power where needed or harvests power from surrounding sources)
4) Information storage and processing (usually cloud storage and data pipelines like queues or streams followed by services that process information and/or store it)
5) All problems above involve additional dimension, everyone's favorite these days - scalability (massive number of devices collecting data frequently, sending it over through communication channels for processing in cloud)
Here's just one simple idea of how IoT can make city better. Imagine a smart waste disposal bin used for compostable waste. It collects information about how much waste is in it and sends the information over to Smart City's cloud "application". Every morning this application forms a map of places where garbage disposal truck needs to visit to collect garbage. It also allocates enough trucks for the work and optimizes their route for the day. This may reduce cost of fuel and reduce truck maintenance cost by optimizing number of trucks used daily. Citizens are happy because their compostable garbage isn't left to rotten (and stink) for long time.
Further more, data analytics team may use the information to extract patterns. For example, how much waste is generated in certain part of the city on a football game day or on bad weather day and use it for truck fleet management.
Of course, this example may be solved in some other way or may not reduce costs at all, but that may also be considered as problem in IoT - how much the solution costs and is it worth it and ultimately, how to reduce the cost and complexity of application so that IoT is more often worth it.
To summarize, IoT is a thing. It may not be necessary in many solutions but in some it probably is good option or will be. Still, for sure, it's a thing.