iOS 13 drops support for the 6. It'll be 6s/SE and above for iOS 13. It'll be interesting to see what they do for iOS 14. I was surprised that they cut off both the 6 and 5s this year.
t’s not really a huge deal to me that they’re likely purposefully going to try to keep the newest iOS limited to only a few years. Supporting 4 year old devices is still pretty good. And being on an old iOS for a few years isn’t the biggest deal.