No. What you do is look for bottlenecks and see if you can eliminate them with minimal cost. Most of the time you can.
Most of the time, you can't.
Tell me how you can upgrade your processor to 2x the performance for the same number of cores?
You can't. You buy a new CPU, and with that, probably a new machine.
For example, for a gamer, the cpu will not age as much as a graphics card. A sandy bridge cpu from ~2010 is enough for nearly everything, but a graphics card from that era will be junk. There's zero point in replacing the whole machine.
Games CPU, is that even a thing? It only runs games? It has special features that shoot lasers?
You can't replace just the GPU and expect better everything, all you are going to get, it's better frame rates, and also the GPU will be bottlenecked because your CPU isn't capable of doing the AI, game logic, etc. and then make all the draw calls of your brand new Graphics Card.
Also, the memory won't be able to fill the graphics card memory in time for the frame.
The ssd may be bottlenecked, but he's still got a huge performance increase with minimal cost. Also, the drive will probably outlive his motherboard, so he'll get additional benefits down the line.
I won't argue, but still, if you are paying, let's say $200 for a brand new SSD, you are still only using $100 to $150 of it.
What's the matter of an SSD on a Core 2 Duo, yes, it will make it faster, but it won't make it a new processor, it won't make the whole system better. Yes, it's cheap, but it's better to put that money on the piggy bank and spend on a next generation computer when your PC will be obsolete.
Or even better, just buy a better internet service, if you can, it's what people really use computers for...
Also, gaming on PC, is a waste of time and money.
You get so less bang for buck than a console, you have problems, the games are made to be as heavy on GPU's as possible, for the hype, and for the GPU manufacturere's money, which is evident. Whilst on consoles, they keep going and going year after year, you'll never have the urge to update your hardware to just play a new game... But that's me, I'm 27, so...
----------
I want opening my computers and upgrade them to last like fridges or an oven. Ok, not so long, but a computer should last around 6-7 years after some upgrades. 10 years would be nice.
Heck, my mother still uses a 2007/2008 Toshiba laptop as a "desktop" computer (she also has a Samsung ultrabook). I'm planning upgrading it to 4GB, a SSD and perhaps a new battery or even its processor, so maybe it will last up to 10 years. After all the upgrades it would cost a fraction of the cheapest Mac laptop.
US Prices:
- RAM: ~60, DDR2 modules
- Battery: ~20, 3rd-party
- SSD (120GB): ~65, PNY XLR8
Total: 145,00
Cheapest Apple laptop:
$849 with student's discount
Ok, there are tons of other factors involved, but all of you would agree that the above upgrades would keep a pretty old computer on par with most software needs (browsing, office stuff and so on).
What's your Internet bandwith?
That isn't enough even for browsing with a 100Mbps bandwidth, let alone more complex tasks...
And did you get an upgraded screen, upgraded chassis, a battery that lasts for half a day? A new everything? Is the RAM even DDR3?
No.
So you wasted $145 on an old machine, and made your mom's next laptop $994 instead of $849... congrats.
. 
