A 2010 Mac Pro has more than enough power to run the upcoming version of Mac OS, and quite likely any system software Apple releases for the next two decades. I know the 80s and 90s had us replacing our computers every few years, but we've hit a relative plateau over the past decade, and claiming that an 2010 8-core Xeon can't run what a 2017 dual-core i5 can is just disingenuous.
I'm not saying don't innovate or update. But I despise the throwaway culture we live in. I'm in the small minority, but I'd like to see computers (especially one's that cost more than $1000) come to be viewed as appliances more than apparel (think about it). When I buy a refrigerator, a couch, or a car, I expect it to last me 15-20 years. I will pay for quality engineering, but in return I'll determine when to EOL my property.
This is the philosophical problem I have with Apple and most other companies in the hardware and software industries. Most people don't seem to notice (or mind) that they're being fleeced, and the analogy of the frog in the boiling water is not out of place here.
I agree with you overall, but I think the car and refrigerator analogy is flawed. I have a Mac Pro from 2010 and I think it's sad that it won't get 10.15, but I do understand that computers are way more complex machines – both hardware and software wise – compared to refrigerators. I don't know the exact reason for Apple omitting the classic Mac Pro's in the coming MacOS, but maybe there are good reasons for doing so? I was thinking it might be related to the processors not getting any micro code updates from Intel for the lates security concerns found in their processors, but I don't know...
2010 and 2012 Mac Pros are excluded; likely for all of the video card upgrade gymnastics that had to be supported to enable them to run in Mojave.
The video card gymnastics has already been done to get them to run Mojave, so I don't see that as a reason not letting them support MacOS 10.15. Must be some other reason(s).