APS (film) was introduced in 1996. Its design phase I reckon should date back to at least a couple years before. Digital photography was in its infancy.
If the market it was aimed at was the P&S, why choose the APS format? There was no APS format digital camera in the P&S market.
If the market it was aimed at was the "mature reflex" camera, then why the APS format? In 1996 there were no DSLR as far as I can remember.
Who could predict the APS format would have been dominant in 6 or 8 years?
In general, I find it difficult to believe that in 1996 Kodak, Fujifilm, Minolta, Canon, Nikon etc. were so much involved into digital photography as to base the dimension of the film format on the needs of a very future, or futurible, digital revolution. I mean the mentioned "planning" was likely to be at a very pre-pre-pre-production stage and not in such a stage as to influence the film format which could have been dominating the film market for decades.
In hindsight we know that digital prevailed and that APS format prevailed (so far) within digital. But in 1996 (or before) one should have been a real witch to predict the future.