For example, I only buy/use old high-end (for their day) business class laptops and put linux on them. They work for everything I need to write and surf.
I also bought an iPhone that was already a few years old and plan to keep it until it stops getting security updates from Apple. I also moved from Android to Apple not because I like iPhones better (I don’t, really), but because the years of security updates (versus maybe one or two, on Android) matters to me.
The issue seems to be that the build-it-yourself market caters almost exclusively now to the gaming crowd. If you want a gaming PC then you can still get a good deal building it yourself, but if you just want an inexpensive computer it’s going to be tough to beat a prebuilt.
The last time I built a PC for myself was 2012 and I’ve been looking at replacing it. I have to say the state of the DIY market today compared to 10 years ago was a bit surprising.
You are right. I’ve been browsing sites for PC parts the last several years, just for fun. And it never dawned on me that almost everything on them was trying to sell gaming-relevant components.