1. Silicon transistors do not function at voltages much higher than about 1,000 volts (SiC devices can be worked as high as 3,000 volts). In difference, electron tubes have been developed which can be operated at tens of thousands of volts.
2. High power, high frequency operation, like which employed in over-the-air television broadcasting, is better acquired in electron tubes because of enhanced electron mobility in a vacuum.
3. Silicon transistors are more vulnerable than as compared to electron tubes to an electromagnetic pulse produced by a high-altitude nuclear explosion.