Being able to add RAM and replace storage with faster flash typically extend the useful life of a computer, even if the CPU is not replaceable as in desktops.

On my machines the limiting factor is not CPU, but memory and GPU speed. Low RAM and slow GPUs prevent me from running local AI models. These things will only get bigger over time. I wouldn’t expect a developer machine to still be useful 5 years from now with less than 16 or 32GB.