Our narrower-key piano was what I would do all my practicing on. I didn't really know the difference at the time though. It was just a piano to me. While practicing, I'm sure I benefitted from being able to reach farther than I would on a standard size keyboard.
But only while practicing. When it came time for performance, whether at church or at recitals in the music hall in the city library, the number of mistakes would shoot up. At the time I attributed it all just to nerves, but years later I realized I wasn't performing on an instrument of the same dimensions as the one I had practiced on. Having to switch your muscle memory like that is a tall order.
So we've got these options:
1. Everywhere that there's one piano today, have three instead (as the article suggests), so people can pick the size they want to play.
2. Get a smaller one for yourself, and assume the risk of increased mistakes when performing on someone else's full size.
3. Choose consistency over greater reach, and practice on a full size.
Some places could support option 1 (universities and symphony orchestras, perhaps), but it seems unrealistic for most homes, churches, and piano teachers. And I doubt that many concert halls with Faziolis ($100k and up) would be very excited about needing to buy 3 of them.
With electronic instruments it becomes a lot more feasible. MIDI controllers already come in a variety of key widths. This market is competitive enough that if I were part of PASK, I'd start here and try to convince a manufacturer to claim this niche.