I don't know about it being a new, up and coming thing. Some manufacturers were using motor driven cable slideout mechanisms in the late '90s, because I was seeing them on used RVs of that era when I was shopping in 2004. They also used motor driven rack and pinion, and motor driven screw jack mechanisms in that era, and likely still do.
Hydraulic rams were initially used on heavier slideouts, a category which would include the first used on motorhomes by Newmar.
I was seeing cable pull on slideouts that were small enough to be hand-cranked, but not small enough or light enough to be simply pushed by hand. RV industry experience with cable systems goes back to moving the roofs of pop-up campers, where the technology is still widely used.