No. PSUs do not get obselete. The technology that PSUs come from is not the same as the technology for smart phones for example where there are always advancements.
When it comes to the technology for PSUs, it is mostly on increasing the efficiency of the PSUs so that we have a PSU that is taking in for example 100W of power from the wall and giving maybe 86% of it to the PC components inside.
In the PSU world, that is what the 80 Plus certification is all about. It is about the efficiency of that PSU in passing the current and wasting as little current as possible which can result in higher electrical bills.
Well, that is why I went with my Seasonic Prime Titanium series. The highest rating a PSU can get. It means that it's efficiency is at least 90% and above when it is getting 20%, 50% and 100% load.
You can learn more about it here.
https://www.velocitymicro.com/blog/what-is-psu-efficiency-and-why-is-it-important/
This is why in the PC world, you can get almost any PSU you want. Even old ones for as long as there is an 80 Plus certification to tell you just how efficient that Power Supply is.
But do take note, cheap brands tend to use components that are not long lasting. And some tends to run hot.
That is why in the Japan tends to make the best capacitors for these kinds of electronic parts. Highly recommend you with with brands like Seasonic and its Prime Titanium series (newer model comes with a slightly different name) as it can last you a very long time.
Bought mine back in December 2016. Working great and quiet even till now. No problems whatsoever too. So am very happy with it.
Just consider the PSU as the "buy once, and forget" kind of PC component purchase. Cos it is just that good and long lasting.
