In recent years, a strong increase in publications in scientific journals can be observed as well as an increase in the number of conferences and publications there. On the other hand, the number of completely new, innovative sensors that are launched on the market every year is relatively small and constant. This paper tries to look at some aspects what this gap is caused by. Requirements for the characteristics of typical sensors are considered and demands on the development of marketable sensors are derived. The industrial usability of sensors requires that the manufacturing technologies for their production are mastered extremely reliably and reproducibly, i.e. that the maturity of technologies, i.e. the Technology Readiness Level, has to be very high. For this purpose, the underlying physical processes must be extremely well understood. Against this background it becomes clear that the development time from the first idea for a new sensor principle to the marketable sensor and then to the mass product usually takes many years, often even 10-20 years. The current exponential growth in publications in the field of sensor technology is in no way coupled with a corresponding increase in innovations. On the other side, the increase in the number of fabricated sensor devices seems to be driven mainly by the larger and larger demand on sensors in all areas of industry and technology and not by an extraordinary increase in innovation.