Quite often, developing an application requires more than an RTOS:
- Storing data in flash memory
- Handling integrated radio interfaces (Wi-Fi, Bluetooth...)
- Using one of the IP protocols (TCP, UDP...) over some networking layer
- Using some messaging protocols (MQTT, CoAP...)
- Logging
- Updating the code in the field (FUOTA - Firmware Update Over The Air)
- Artifical Intelligence tooling
- etc.
The availability of such middleware components depends on the RTOS.
Some components may be generic (RTOS independent) but may require some integration.
⇒ Check the ecosystem against your needs before choosing an RTOS