I am not suggesting it is a battery issue with my iPhone 11 Pro Max. As shown in attachment, iOS shows the battery is 99% and a third-party battery test app also confirms the battery is in great shape.
View attachment 1930974View attachment 1930975
As I stated in the previous posts in this thread, my iPhone 11 Pro Max suddenly couldn't connect to WiFi APs in my own house and it was the only device (out of 20+) that had issues with WiFi. It became very slow too. This happened after I upgraded it to iOS 15.x. I contacted Apple Support and it got escalated to a Sr. Advisor. He suggested that I did a backup with iTunes, erased the phone completely, and recovered from the backup. That fixed WiFi issue but it remained quite slow.
That was when I posted my query here. Then I upgraded the iOS to 15.2. It seems to improve the performance a bit. What does this tell me? IMO, Apple has not done enough to ensure 2-year old phones operate reliably with their engineering effort. This is similar to the 6S fiasco showing Apple has strong motivation to make us upgrade to newer phones, above the rest.
Why wouldn't Apple develop battery weak warning for 6S? It would have cost them more to develop the software and it would yield less business return. They are doing it now because they got caught.
Why wouldn't Apple ensure my 2-year old iPhone 11 Pro Max work reliably after the iOS 15 upgrade? It would have cost them more engineering resources to ensure that. IMO, Apple did not spend sufficient engineering resource to ensure older phones with various configurations to upgrade reliably. Some older phone owners may just upgrade to the current models which would definitely benefit Apple more.
IMO, this is a near-monopoly business practice. To be fair, Apple is not the only company that does this. In fact, this seems to be the common practice. I work in the tech industry and have seen this many times. But this is a forum about Apple iPhones.....