Could upgrade your PS4{specification}

[EpicGamer835]

I wanna know if we could change the graphics card on our ps4 or any other console.

I know if would change it would lock at 60fps only but it will be  locked at 60fps. So, could we just upgrade our last gen console with new graphics card or ram....

[SkilledRebuilds]

Beyond Storage,... Never going to Happen.
a Used PC akin to the PS4 or better to which you can upgrade GPU's accordingly is why PC gaming is a thing, options.

Sadly for those that want it,...it won't EVER be a Console thing to buy a new GPU only and leave the base system, they usually would be quite unbalanced doing so anyway (up until these new console CPU's are out), but it comes with too many issues, and concerns to be undertaken by manufacturers.

[PlayStation 2]

The only thing you can upgrade in a PS4 is the storage. As a matter of fact, Sony makes that pretty easy.

The only console I can really think of where the hardware was upgradable to some extent outside of modules like the Sega CD and the Atari Jaguar CD is the original Xbox. There's various mods out there that allow the user to throw a 1.4GHz Pentium III and 128MB of RAM in it.

[SkilledRebuilds]

Offtopic but alternatively aging,.. RAM Upgrade for a Console has been done before.
https://en.wikipedia.org/wiki/Nintendo_64_accessories#Jumper_Pak
This^ and the second "Expansion Pack" paragraph below it.
The Nintendo 64 Expansion Pak (NUS-007) consists of 4 MB (megabytes) of random access memory (RAM)—which is RDRAM, the same type of memory used inside the console itself increasing the Nintendo 64 console's RAM from 4 MB to 8 MB of contiguous main memory.It is installed in a port on top of the console and replaces the pre-installed Jumper Pak, which is simply a Rambus terminator.

The expansion pak is merely used as additional framebuffer memory to enable various high-resolution (usually interlaced) mode options, at the downside of usually worse performance, in some cases dramatically so. This common simple use of the Expansion Pak can be attributed to ease of implementation and the fact that games still mainly targeted the stock N64 configuration; also, the additional RDRAM could not be easily used to circumvent other bottlenecks of the console, such as the small texture cache.