For someone just getting into gaming, choosing between a console or PC, is tricky.
Maybe its the kid who got his first job and wants to buy into current Gen gaming.
Maybe its an adult who has been out of gaming for some years. Who knows.
But the idea of being able to salvage and upgrade an old computer, is very, very circumstantial.
People with PCs that can accept upgrades, probably already have a custom build in their house. And therefore probably already have ties, even if familial, to PC gaming. Yeah, a lot of people on this forum probably have access to an old custom build. We exist in a bubble.
The amount of viably upgradeable desktops from dell, Lenovo, etc are quite small.
And that's if people even still have a desktop around. Many people have laptops in their house. I worked at Staples in 2013 and we were selling laptops 10:1 against desktops. There were also many people looking at tablets to avoid laptop or desktop, at all.
But lets have a look at the family Dell or Lenovo desktop, which has survived being replaced by a laptop. Heck, it might have an 2500k, or even better, a sandy or ivy bridge i5 in it. Shoot, it might even have an i7.
Does it even have a slot for a gpu?
Is it a slim tower? You have one choice for an upgrade and that will put you right about even with a PS4. And that's if the slim towers even has free space around that GPU slot.
But, what's that slim power supply like? You may not even be able to use that one GPU choice.
Does it have 8gb of ram? If not, is there a free ram slot? or will we need to buy all new ram to get 8gb in there?
Ok, its a regular tower and has a gpu slot.
What's that power supply like?
Is the inside of the case layed out in such a way, that a regular width gpu or larger power supply can fit?
Or, the CPU is good, the mobo has a gpu slot, but we need a different case to get a gpu to fit or a new power supply but-----oh wait, the motherboard isn't atx standard. Will it fit into an aftermarket case?
What if you have to reinstall your OS? Will you be able to figure a way to turn your restore partition into a fresh install with the new hardware?
Will the motherboard even allow hardware or OS changes? Dell, lenovo, HP, etc have all been known to have microcode I some modles, which restricts such changes.
There can be ways around it, but will Joe upgrade even know what he has just run into? And does he know enough to be resourceful enough, to otherwise figure out the way around it?
I have worked on a very high end dell workstation, which had special data cables which made the hard drive appear to run on a proprietary connection. It was actually a normal HDD. But you really had to get in there and totally take it all out, to see that.
This isn't easy stuff. Unfortunately, the open platform idea of a PC is a product, is a market segment. Not a rule.