However, I doubt many folks predicted the wild popularity of Arduino or Rpi either. All it takes is for some cool applications. The price point isn't a huge barrier these days.
I keep hoping some post-grad will come up with a great DUMMIES like guide that covers Hello World to signal processing.
It starts from the absolute beginning, and the tools and tutorials are web-based and integrated with each other:
The focus is from Hello World to personal computer, but I've built a DSP-based guitar pedal in the past, and signal processing is really fun - I'd love to create a parallel learning path from Hello World to DSP at some point.