As per a survey result by Tech Navio and Deloitte, the revenue generated by the Internet of Things in Germany from 2016 till 2020 is in billion Euros.

The revenue generated in 2020 was expected to be around 50.1 billion Euros. The number is remarkably high as compared to 2018. The demand for smart factories definitely needs IoT devices a lot in Germany.
As per the IDC survey result, around 1000 billion dollars is expected to be spent across the world on IoT devices. In 2019, 745 billion US dollars is spent on IoT devices across the world.

The IoT market is diversified. Hence, a lot of opportunity for industries to spend a huge amount of money in various sectors such as consumer, business: Cross-Industry and Business: Vertical-Specific.
As per Gartner, the number of devices used is in million units in each sector.

In my opinion, the market is valuable and has an immense amount of growth. The importance of the IoT is not limited to one industry but is being diversified into other industries also.
Source:- Statista