I understand that they were trying to make a pretty complicated topic more approachable, but I always felt the push to GUI was misguided. Maybe they would have had more luck embracing the “S” in “SDR” and making programming languages the primary development paradigm.
If you have a certain DSP goal in mind (say, RF comms), and you want to do stuff but not absolutely balls-to-the-walls processing (at that point, presumably you'd move to hardware), you can design your stack in fairly modular and composable ways. The field is pretty mature and the techniques just work.
In a software context, you can decompose the abstractions fairly cleanly. You won't get 5G high performance networking but you can get good enough results.