I'm just curious why you are unable to update the version of Android on your phone? My phone runs Android 10, but from what I've read, the actual hardware is capable of running much more recent versions. But the phone has no mechanism to update as this is set by the manufacturer in it's settings options. I personally am convinced it's to force consumers to buy a newer phone at regular intervals.

Am I right that this is some kind of planned obsolescence?

The manufacturer of the SoC (processor) in the phone often only provides a few years of driver updates. That time frame is based on release, phone manufacturers often use year or two old chips in their phones unless it’s the flagship product. 
 

The software on your phone does not run a standard version of android. Android is not like Windows where it can be installed to any compatible hardware and configure itself or tell you what’s missing for you to install yourself. Android has to be built as a rom (single software package) for your specific model with all the necessary drivers and manufacturer customisations. 
 

You are therefore at the mercy of your phone manufacturer to build, test and deploy updates which they don’t often have much incentive to do. This is probably Androids biggest problem. Google have tried to make the underlying OS code more modular so it takes less work to update, or working with manufacturers to try and provide more updates. But again once they’ve sold the device, there isn’t much incentive. 
 

You can build your own roms or use third party roms, this is Androids biggest strength as it is open source, except many manufacturers lock bootloaders to try and prevent this. The issue with third party roms is that they are not signed off by Google, so things like banking apps and anything that deems itself handling sensitive information will not work on third party roms. At least not without trickery which is a bit of a cat and mouse game. 
 

I used to enjoy running custom roms. Google used to actively encourage it on their phones. Then things started getting more and more locked down and harder to do that sort of thing, or even if you did so many apps didn’t work without googles sign off or frameworks I gave up and switched to iPhone. Apple at least gives all their phones 6-7 years of updates and they are all updated at the same time. 

On 4/6/2024 at 9:44 AM, StephenFord said:

Am I right that this is some kind of planned obsolescence?

From what Alex has just said you are clearly bang on the nail.