I see a couple of scenarios:
1) Generally when an Apple product goes neglected this long, it's for the chop. It's a reasonably priced, low volume and probably low margin Mac so they're not going to be particularly interested in investing R&D into it.
2) However sometimes they do have a long gap when they're trying something new. Perhaps the first ARM based Mac, with a more locked-down system (e.g. Mac App Store only, no downloaded applications) so that the money they don't make from the tight margin is replaced with app store revenue.
Could be, but seems like a lose-lose for all of us Mac mini fans.
I think a lot of Mac Mini and Mac Pro buyers don't want either machine, they want the non-existant "Mac" - a mid-level desktop with no built in monitor.
I ended up buying a 2017 27" iMac to replace my 2006 Mac Pro, but I really hate the all-in-one concept (especially with no Target Display Mode).
Yes, that would be ideal (heck, the current Mac Pro would be fine if it had TB3 and cost a bit less). But, just something like the 2012 Mini with current processor and ports would be just fine.
I also agree with the rest of what you said about the iMac. I had one, but sold it as I don't want a single-use display. It's great for most people, I suppose.
Apple is really leaving us computer enthusiasts (who don't use iOS) no choice but to Hackintosh or leave the platform altogether.
This is getting ridiculous.
I'm serious, why stay?
Because the grass isn't greener.

If it were, I'd be long gone.
Does Apple really have that much power over your life? Why do you willingly give a tech company that much power?
If Chevrolet does not offer an automobile that meets my needs, I would look at other automobile manufacturers and find one that does.
I don't, but what's the alternative? There are only two viable choices, and the other had plenty of problems too. What we're here screaming about, is seeing the one option that used to be pretty much truly a great option, degrade so rapidly.
As others have noted, the analogy doesn't hold, as in the automotive world, there are a ton of choices and the switch is easy. That isn't the case with computers and OSs.
Do they sell enough SE iphones? I hope it doesn’t go the way of the mac mini. I tried to find a used SE and there are almost none for sale in my area. 6 and 7s? Lots.
The problem is that the way they rigged it, they won't know. They made the SE the high-end-budget device instead of the 'good form factor' device. So, if it sells a lot, they'll conclude it's because of the lower price. If it doesn't sell that well, they'll conclude people want the main iPhone line as is.
You're right but as far as Im aware. Majority of the apps and other things work fine on Windows including iTunes just as they do on MacOS.
It's about so much more than that, though. Workflow, UI/UX, etc. and yes, sometimes specific apps that aren't available.
I wonder what they do with their billions in profit every year. How hard is to come up with a new Mac?
What do you have your 100,000+ staff doing everyday? Even if you have a 1/50 of your staff working on the Mac thats still 2000 people...
Poo emojis, Car Karaoke, Apple Car, 'space ship' buildings....
There are just so many more important things to do if you don't care about the Mac any longer.