I pretty much agree with your assessment. The one kicker, and one which no one really has a good grasp on, is just what exactly the few odd comments about a "modular" Mac mean in terms of the future of the desktop line.
Apple made no real comments about the "desktop line" as a holistic thing. The modularity comment was aimed directly at the Mac Pro.
"...As part of doing a new Mac Pro — it is, by definition, a modular system — we will be doing a pro display as well. ..... We think it’s really important to create something great for our pro customers who want a Mac Pro modular system, and that’ll take longer than this year to do. ..."
https://techcrunch.com/2017/04/06/t...-john-ternus-on-the-state-of-apples-pro-macs/
Sweeping modularity across whole desktop line up..... completely not there at all. The display being "by definition" an aspect of the Mac Pro's modularity is also relatively clear. If Apple detaches the monitor then the resulting system is modular. Could it be "more modular" by extending that to internals. Maybe ( they are not clear on that. Neither ruling it out or adding it). However, it is clear that the will have accomplished the definition if the monitor is. [ The objective in that meeting was
not to talk at length about the details of the new Mac Pro. ]
Lots of folks too that passage and morphed it into the Mac Pro has to look almost exactly like the 2010 model. That is not what they explicitly said at all. Other folks have morphed that passage into something like "Apple says that modularity is a Pro feature" ( implying "more Pro" means "more modular" ). Again, they didn't say that at all. Monitor would likely work with the vast majority of the rest of the Mac line up (if not all of it by 2019-2020 if the Macbook picks up Thunderbolt. ). Docking a MBA to a monitor doesn't make it "Pro" in Apple's definition of Pro.
Will there be a headless line that ranges seamlessly (and thinly!) between a Mini end and a Pro end in some progressive fashion?
No. Later same talk.
"... I think, as you talk about the pro user, the fact that our user base is split over notebooks, all-in-one desktops and modular desktops is important. We aren’t making one machine for pros. We’re making three different designs for pros. We’re going to continue to. ..."
MBP, iMac Pro (which was "upcoming" at that point of this talk ) , and Mac Pro. Three. To reinforce earlier in the talk
"... First, we’ve been talking to Mac Pro users – and the rest of the pro users: iMac users, MacBook Pro users. ..."
and
"...
Notebooks are by far and away our most popular systems used by pros.
Second on the list is iMacs — used by pros, ....
Third on the list is Mac Pro. Now, Mac Pro is actually a small percentage of our CPUs — just a single digit percent. However, we don’t look at it that way. "
Three. Are there folks who a "pros" who use the Macbook , MBA , and Mac Mini? yes. However, it is a smaller share of the folks who buy those products. What Apple is probably talking about with a "more focus on Pro" with the mini is tweaking that percentage upwards. Probably still will be dominated by the non-Pros overall, but higher end "Best" standard configuration and BTO options will be "Pro" targeted. The result will be an higher average selling price for the product.
Higher average selling price would mean the volume would not need to rise up to swamp the iMac, but still could boost the overall ecosystem.
Will the Mini be outside the modular line?
If modular by definition is no monitor how could the Mac Mini be outside the modular line up? It has no monitor so therefore it is in the modular line up.
Again I think a large amount of this "confusion" is driven by folks presuming that "higher internal modularity" == "Pro". That is not how Apple defines those terms. "Pro" largely means folks who use the Mac to make a living. So a Photographer who is getting paid to do a shoot who carries along a MBA to do field backups and quick inspection of photos is a "Pro" user. They don't absolutely require a Mac with the word "Pro" printed on it to be a Pro. Likewise, a MacBook Pro doesn't have to have high internal modularity to be a "Pro" model. Modularlty and "Pro"-ness are two different dimensions.
A roadmap for the raggedy-assed masses would be very nice.
Apple's corporate policy about not talking about future products in detail has an implicit constraint to work well. Apple has to
do something on a reliable and reasonable schedule. The policy is a 'talk' by 'doing' rule. The approach of going into 'Rip van Winkle" mode for 3-5 years at time and then pop up to disappear again is inherently in conflict with the "don't talk about new product" rule.
I think Apple's has been trying to adjust to users buying classic PCs form factors at a slower rate. ( one keynote Schiller snapped on Windows users having much longer initial user life spans but Apple has to be feeling the same trend rising. For lots of folks, computers are "fast enough" for their workloads and the workloads have plateaued in performance demands. ) . So they went to a do less with less model where just cast some Mac models adrift for years at a time and put more resources on other efforts. That has not worked well overall ( the negative effects are now starting to present. For a while it was "Emperor's New Clothes' at Apple where some must have thought it was working. )
The other problem is these targeted leaks get blow way out of proposition even with they do try to set future expectations. This "pro focus" on Mac Mini wasn't trying to signal the coming of the xMac mini tower. What Apple started selling "Mac Mini Server" it was still primarily a "Mac Mini". ( Perhaps Mini gets incrementally taller to incrementally expand the thermal envelope, but it isn't going to turn into a system focused on easy access to most of the internal parts. ). Folks on the outside injecting what they want to hear into the minimal stuff that Apple does say; in part that just reinforces the "say nothing" rule.