I’ve never heard that RTOSs are the future in general. With that said, there are a lot of great RTOS options out there today.

1) PREEMPT_RT recently brought realtime capability to mainline Linux[0].

2) Amazon open sourced the safety-certified ThreadX[1].

[0] https://en.m.wikipedia.org/wiki/PREEMPT_RT

[1] https://en.m.wikipedia.org/wiki/ThreadX