It's just proof of planned obsolescence. For phones it happens one way, for TVs another way.
It‘s not. Instead it‘s the only reasonable way to deal with degrading batteries - a limitation all manufacturers have to deal with. Apple opted to prevent unexpected shutdowns by slightly throttling performance - the correct decision for most users, but they didn‘t tell the user about it, which of course serves as a great excuse for colorful, exaggerated headlines like the one in your linked article.
So do you have a magically solution to keep rechargeable batteries from degrading over time?
yes.
a replacement battery.
And you can get a replacement battery for $70. I got one for my 6s after two years before the whole batterygate thing started because it wasn’t holding a charge. Between my son and I, we kept it for four years. The only reason I didn’t keep it for another year was because I wanted a larger phone with a larger battery.