Care to cite any sources as I'm only coming up evidence that they don't (the last one is a forum like you said and the reasoning explained there is due to bloat)

https://mashable.com/2018/01/04/apple-slowing-down-iphones-w...

https://www.theverge.com/circuitbreaker/2017/12/29/16829512/...

https://www.engadget.com/2017/12/29/samsung-lg-claim-older-p...

https://forums.androidcentral.com/samsung-galaxy-note-8/8589...