Jean-Louis Gassée is back, making his predictions for the future of Apple’s operating system plans, which he sees as heading inexorably to a combined form of iOS becoming Apple’s OS inside all Apple devices.

This follows similar arguments made by the former Apple exec and Beos founder, when he argued iOS would evolve into the operating system for future Macs.

“Today’s Macintosh is the result of more than a quarter century of evolution, refinement, fixes, and additions. It’s highly functional but complicated, perhaps needlessly so,” he writes. Comparing the OS on a Mac with that of the iPad, he notes that on the iPad things are so transparent users forget there isn’t a Finder, just icons.

While Gassée doesn’t expect any immediate move to march out with a fully combined iOS/OS X hybrid, (the iPad-like improvements within Lion is cited in the report), he argues, “Over time, iOS version 7 or 10 will become the operating system that runs inside most Apple computing devices.”

“The careful application of a common veneer on both Mac and iPads is, in my interpretation, a preparation for a transition to a shared OS, or to variants of the same underlying software engine adapted to the two usage modes: Lean back and lean forward.”