Pomgolian .... Wrong... Re: That probably explains..
There are two things happening...
1) Moore's law which is still holds true... (to a point)
And product design...
Please don't conflate these with what is happening...
As newer, more powerful CPUs are created, more features are added because the phones can do more. Your older phones are having a harder time running with the latest versions of software because of their slower, less powerful CPUs. Also, the more horsepower, the more likely that sloppy code works well enough and added features that you really don't want aka bloatware...
And then there's product design that wants slimmer cooler look and feel. If you don't believe me... if two cars cost the same... one ran like a tank but looked ugly, or a sleek model that does a better than good enough job... which do you choose?
NOW HAVING SAID ALL OF THAT.... APPLE WILL LOSE OR SETTLE THE LAWSUIT...
All of the issues that you raise are true of all PC tech products. (see above)
However, the issue is that they are throttling you because your battery is supposedly starting to fail. Because of the product design, you are unable to DIY battery replacement, thus you have to pay for the service time in addition to the battery. (and the warranty that it was done right and the phone sealed back up properly...) So you can purchase a new battery. Much cheaper than a new phone.
At the same time... if you do purchase a new battery, your phone will still be throttled. So how are you protected? You're not. There is no way for Apple to know if you've replaced your battery or not therefore your phone will still fail.
A judge, or a jury will see thru their argument.
If they didn't do this... you would still have a choice and of course many would go to CPR (a third party phone repair service) and replace the phone battery. Or you could upgrade your phone because your older phone would be less capable of running the newer apps that you want to have or your kids say are 'must have' apps.
(You could go to Apple, and it would be smarter because some of these places use cheap knockoff parts that well... could cause your phone to explode or catch fire. ... re. USB charging cables (remember that fiasco?) ... )
Because Apple doesn't allow this path... they will lose the case and you can bet that if you bought a new iPhone... you'll get some sort of credit at the apple store, or a coupon/rebate... all while the lawyers get millions in a class action lawsuit.
IMHO, Apple and others in the Silicone [sic] Valley need to wake up and get a reality check.