Modern laptop motherboards can easily be about the size of a cell phone. Most of the case is battery and the main board is a shrinking percentage of the BOM cost. The entire motherboard is the replaceable component. It’s less “right to repair” than the additional components and design required to make them repairable are more expensive than just replacing the whole board.
Seems like a deliberate design choice, not some inevitable consequence of modernity. Why exactly does the board need to be cell phone sized when the actual form factor of even a netbook is substantially larger?
Which you could also do by simply making the device a little thicker and have a battery run the entire width of the device. Point is past a certain point, thinness becomes more of a drawback than a benefit, especially given the trade-offs involved.
You might want that trade off, but consumers in general have been leaning towards thinner and lighter for years. Just look around at complaints about the thickness of early android watches being too big and chunky. Or the huge popularity when the first MacBook Air came out.
Given the option between thicker w/ a bit more battery life or thinner and lighter, consumers are choosing thinner and lighter.
Of course engineering is always a trade off, and it is possible to go too far in one direction. But it's not all or nothing, Apple is the one feeding us that false dichotomy.
> ...consumers in general have been leaning towards thinner and lighter for years.
> ...consumers are choosing thinner and lighter.
A) I'm guessing actually lighter more than thinner.
B) Are consumers really clamouring all that intensely for "Thinner! Thinner!", or is that a) because that's all that's offered, and b) the relentless hype from manufacturers -- above all, bendy phone maker Apple -- amplified by rarely-critical media?
Battery is a big part of mobile devices of all kind, but it's not “mostly battery” for most of those.
For instance, in a iPhone 11, the battery occupies less than half of the surface of the phone[1]. On a Macbook pro, it's about the same.[2]
[1] see this ifixit video if you want to see it by yourself: https://www.youtube.com/watch?v=Feyqwf3cYtw&t=161s
Looking at the picture from [2]. it looks like the motherboard is really not much much bigger than a smartphone. There's a lot of space dedicated to ventilation (note the two large fans and the black cooling ducts under the hand in the picture. Some fraction of that motherboard is also the solid state storage. The picture here of the internals of an iPhone 11 https://www.zdnet.com/article/heres-whats-inside-your-new-ip... (I don't do videos) sure looks like it's mostly battery. If I discount the empty space, the insides are more battery than not battery.
It is mostly only a deliberate design choice in the sense that consumers have leaned towards designs that are smaller, lighter, and with longer battery lives.
It doesn't matter that the rest of the form factor is larger: there's not a lot of empty space in these, so a larger main board will still mean a larger and heavier device.
That’s a laptop from 2 years ago; the new M1 MacBooks are more indicative of where things are headed in the future. Things like memory and any custom ICs are just going to be integrated on the same silicon as the CPU in most cases.
Still bigger than a smartphone (it occupies the entire width of the laptop (when counting the heatsink, 2/3 of the width otherwise), and around one quarter of the whole area).
Also, your original sentence was
> Modern laptop motherboards can easily be about the size of a cell phone.
Here we see that the one and only best laptop in this regard comes close to the cell-phone-sized motherboard. That's far from what “modern laptop can easily be” means. Most laptops sold today have a much bigger motherboard than this.
(BTW, as much as I'd like to see non x86 laptops going mainstream, software compatibility is huge issue for an ecosystem as diverse as the Windows one (and Roseta 2 being too much of a coinflip isn't encouraging…), we might get there at some point, put it's gonna be slow and painful.)
