I'm writing this on a 2013 27-inch iMac. It's slowing down, without a doubt, and I can't upgrade to the latest operating system. Aside from that though, it's still a cracking machine. So perhaps Apple's thinking they made these things too good...
"Only buying a new machine every nine years? Oh, we need to change that". ;-)
Right there with you with a Late 2014. I don't need any hardware for 2022. I also have an M1 mini next to the iMac and that's enough at this point. I can always get a 2020 iMac 27 if I need more Intel power from the Refurbished Store.