The word is Apple tried and failed to bring touchscreen support to macOS, so instead decided to focus on iOS with iPad Pro. Ubuntu tried the same with Unity and failed once again. That makes you realize just how brilliant Windows 10 is - one OS, one UI that scales from a phone, a tablet, 2-in-1 to desktops and workstations.

So, yes, at this point I don't think there will ever be a touchscreen Mac. Shame, really, though the desktop form factor is one where touch isn't all that crucial. Surface Studio like use cases do make it very interesting though!