It did seem fairly unlikely that the Mac team would release an iMac half a year after the iMac Pro and as they work on the Mac Pro and Mac Mini, but I figured that maybe they could’ve just done a cpu refresh and thrown a touchbar keyboard with touch id into the box and called it a day. But since there were few rumors indicating as such, I am not too shocked that they didnt release one today, I just wonder: will they hold off mac mini, mac pro, and imac all for one event next spring? I feel like they’d wanna release some new macs before Mojave releases. Perhaps we could see some macs at a september event? Although that seems strange as the september event will definitely have the new iphone and perhaps even a new ipad pro. So I’m beginning to feel as if the spring event or wwdc next year is very likely to be the next refesh.
September is the iPhone iOS event, October is the near traditional event for Macs, and Apple might want to wait till macOS Mojave is out before releasing the 2018 Macs. Modular Mac Pro is due next year and I'd imagine that WWDC is the place that they would drop (or at least announce) that.
As for a touchbar keyboard I would have thought there would be technical/security reasons for not including touch ID on a (bluetooth wireless) keyboard even with the contentiously expensive Touch Bar OLED. You might expect a Touch Bar wireless keyboard but how would it perform when not directly connected to the Mac and not a mandatory purchase as with the MacBook Pros? Just how many people would elect to have a touch bar if it cost $299 on a wireless keyboard? Would there even be enough bandwidth in a Bluetooth connection to send the graphics required?
It makes more logical sense for an iMac to have FaceID but then surely the iMac Pro should have had that from day one as a brilliant product differentiator?
In any case, with the 6 core Coffee Lake CPUs fully available now I imagine that Apple will have to have something in mind for the iMac even if it's as simple as adopting the iMac Pro internals for cooling certain models (eg the 95w i7) for example.
While the Coffee Lake CPUs are available already there's been nothing overtly confirmed about the GPU for the standard iMac which is largely expected to be a minor bump of the AMD Radeon Pro 500 series with an X suffix. I doubt they'd be waiting on a VEGA GPU, but could they be waiting on Xeon CPUs or (more likely) the release of macOS Mojave?
It might be acceptable to wait till October to launch the 2018 iMac if it were to come with FaceID, iMac Pro internals, more remotely Apple could consider widening the iMac Pro line by introducing the forthcoming Xeon E CPUs into a lower entry level iMac Pro, leaving the 6 Core i5 with the iMac.