Re: iPhone 12s
Maybe, but the iPhone 6 only had 1GB of RAM whereas as the 6S had 2. The 6S, whilst looking near identical to its predecessor, had a significantly faster processor. I think these factors might explain why support for the 6 has been dropped.
It's hard to imagine the iPhone 12 S boasting such a leap in specs over the 12 that it will have a significantly longer period of support.