I frankly don't understand why RAM for consumers is a thing. I don't know of any other popular consumer good that is routinely built by the consumer out of individual components. You buy cars, phones, refrigerators, amplifiers, et cetera et cetera whole. Why computers are different, in the year of our lord 2025, is a mystery to me. This shouldn't be happening, and I am saying this as a hardware enthusiast who builds his own computers since Windows 3.1 days.
Just like car people buy off the shelf cars the customize them, many of us will buy off the shelf computers and upgrade their RAM, SSD, GPU, or CPU. Maybe all 4, or more. For desktops that aren't Macs, I usually buy used and plan on bring my own SSD and GPU at a minimum. For laptops (again that aren't Macs), I also tend to buy used and plan on upgrading the RAM or SSD or both.
I might not have built my car myself; but have made several after market upgrades to it. My current car features an after-market head unit and tire pressure sensors that I installed myself.
Computers are just the most obvious example because they are expensive, easy to assemble, and have a high markup (which can be obscured on Tim's like now, as there is a larger lag time for component price increases to effect them).
Why shouldn’t it?
Why should we have to buy a whole new computer if we want to upgrade one thing?
The car example is also telling. Yes most people buy pre-built, but the vast majority of pieces can also be bought to repair or replace.
Bicycles are an odd duck where this is concerned -- you go to a department store (no, actually don't) or a bike shop and buy a whole bike as a single assembly. But because there are standards, as others have pointed out re: computers, it's very feasible to just buy all the parts individually and piece together the bike that you want (which is what I do). Honestly, working in a hot (or cold, it is Minnesota, after all) garage, sometimes I question my sanity when I'm assembling these things...but the ability to fine-tune what you want and not be beholden to the standards of some marketing department or the cost-cutting assholes that run private equity funds is quite nice.
Ultimately, I'd love it if there were enough standards out there where I could spec out a car, and have it built up from parts...or just buy a stock one, if that's what I wanted. I feel that way about a lot of products that I interact with -- appliances usually have shitty UX, car software is usually garbage, and I'd love it if I didn't have to rely on DJI for a drone (good luck getting them in the U.S. anymore, anyway).
I think that with any product there's a subset of people who are like, "Eh, good enough," and willing to buy whatever the big manufacturers are pushing, but there's a smaller subset that wants to really dial-in something that fits their needs.
I'm not going to get too far into this argument, 'cause... just no thanks, but I will say that one reason we don't assemble things like cars ourselves is... it's fucking hard. So are pretty much all the other examples you listed. On the other hand, computers are basically giant LEGO with how plug and play they are.
I strongly suspect that if we had phones that were as modular as computers, they'd be very popular.
Huh (Britney Spears head tilt)? Consumers have "built" PCs since the 80s. I was very upset when Apple started soldering RAM to motherboards in order to edge out the competition. Also, people modify and repair cars, I fixed my refrigerator when the water solenoid part failed. Isn't repair and upgrade a normal aspect of everyday life?
wait, what? i buy a motherboard, I buy ram for it. am I supposed to exist in the total vendor-lock-in world? where I have to get a special license to get RAM / SSD?
how is this even an idea
PCs are one of the few things we build ourselves because it's one of the few goods that have standardized and commoditized parts.
If there was a large degree of interchangeability between engines, transmissions, bodies, dashboards (etc) the auto enthusiast community would for sure be building cars from scratch out of parts. But realistically the pieces are tightly coupled and you can't pick and chose.
It's the same with coffee machines - if there were interchangable pumps and boilers and group heads etc, I bet building your own coffee machine would be the norm in a certain crowed.
And to be clear there's good technical, aesthetic, regulatory and business why most large machine's are made of interchangeable parts. I'm not saying car and espresso machine manufacturers have done something nefarious. Just that PCs happen to be free of a major constraint.