I am sympathetic to the argument/feeling that somethings last a long time therefore all things should last a long time.
> What is so special about phones where we allow them to be considered obsolete so quickly?
The phone / computer works exactly as it did when you bought it. What changed is everything around it. That's not true of those other things. New video codex, new services, new sites, new apps. Let's pick ChatGPT. They have app. It's about 2 years old? It strictly costs them more money to cover older hardware than just not supporting it. And, going forward, each year they want to support the newest phones/OS but keeping support for both strictly increases costs. I work on a project that run on nearly every device (Windows/Mac/Linux/iOS/Android) and we are always evaluating which devices we can stop supporting and what new devices we need to add to our testing infra going forward.
Your 18yr old TV is great. It works exactly as it did when you bought it. But for example, let say your TV was 25 years old. It wouldn't have HDMI and there for, without expensive adapters, would not work with an XBox, PS5, Switch (afaik).
The point is, your TV does exactly what it did when you bought it. No changes. For a smartphone to keep working requires constant changes. As a simple example, HEIF images didn't exist before. JPEG's with gain maps didn't exist. Zoom didn't exist. Etc... Your phone needs constant updating. Your TV, A/V receiver, speakers, thermostat do not. It costs money to keep the phone up to date. It costs nothing to keep the TV, A/V receiver, speakers and termostat up to date because there is nothing to update