Q4 2022 was a disaster for smartphone sales, sees the largest-ever drop
arstechnica.com
arstechnica.com
I got a Oneplus 3T back in 2016, and it was already so good that I don't think smartphones have very meaningfully improved since then. I have upgraded my phone, I currently have a Sony Xperia Pro-I, but I'm not sure if I have really gained much. Nowadays there just isn't a reason to get a new smartphone very often if your old one works fine. The same is true for PC's.
At this point I would almost say that smartphones and PC's are a solved problem.