I completely agree here. I would say that POSIX is to software and OSI layers as the PC/104, ATX standards are to hardware design.
Software designers, being the privileged bunch, wags the hardware dog, when the limitations of hardware previously limited software decadence prior to the late 90s. I'm not advocating for dominance of one over the other, but great design requires coordination. I wanted to say "platform independent", but that can sometimes introduce its own issues. I don't think there is such a thing as "too platform agnostic" until it runs into performance and compatibility issues.
A few months ago, Hackaday wrote on the Single Board Computer ecosystem, and lamenting the lack of standards (some which have more to do with connectors that dimensions of the board):
https://hackaday.com/2022/10/05/the-state-of-the-sbc-interfa...
I would add to that, that SBCs are little more than glorified motherboards, with major developers- Raspberry Pi, Beaglebone, Orange Pi, Rock Pi, not all discussing their form factors, feeling a $25 board is too cheap to require a discussion on mounting holes, similar to ITX and ATX. I've built PCs since the 2000s. My first was a VIA C7 with integrated CPU. I still have an integrated ASROCK AMD E-350 in an ITX form factor (E350M1), Which I can use in an ATX case, or a tiny MBox 350 case. A never adopted mobile standard, such as Mobile-ITX, and EOMA68, allows hand-me-down boards to be repurposed into laptop cases, such as the Pi-Top v3. Most buyers of a RPi 3 have a desktop PC, or laptop, and might not use it as one, but at the same time, someone in the 3rd world might, and the laptop form factor isn't going away anytime soon (despite the interest in VR/AR glasses).
Even if some laptops are getting much slimmer than a PiTop v3, there are still many gaming laptops keeping up the bulky form factor alive. One of the failures of the OLPC was the battery life, and that it wasn't really repairable or upgradeable. This isn't to say there needs to be a laptop for everyone, but that a lot of the obvious issues have already been addressed with truly solar powerable computers, such as the Ambiq Apollo 4, which run at 6uA/mhz (and they have plans to develop a linux-capable chip in an Apollo4 like energy footprint). The Raspberry Pi is already a household name, for over 10 years, and yet they are more ignorant of competing boards. If you see all the boards out there- Pine 64, Caninos Loucous, it's like "Join my platform!" We're the virtuous developers, using all GPL software.
But honestly, I don't think someone who has no PC really cares about that- they might, if they had the time to read about the differences between open source, BSD and GPL, but I think the engineers at Broadcom and RPi seem to think that, the environment is an inevitable victim, and not much effort should be spent on component design when it seems like such a low priority in designing something for only 3-4 years of product support, and they aren't even going to think about it after its official End of Life. To that , I say, if someone handed me a bunch of salvaged parts- an empty laptop case, a Raspberry Pi 3, I could put it together. But if someone just handed me a Rpi 3, and a keyboard, and a mouse, and a USB power, and a 720 monitor, and I live in a country with no power, that's not a really practical solution. It's more future proof to develop a form factor that can outlive its individual components. so that while a LCD display on a modular laptop might only be 13" and use 2 watts of power today, it could be designed today, and a future one that can be retrofitted, like a large SHARP Memory in Pixel one, that uses 30mW, could be solar powered. And it wouldn't require buying a new laptop case. (For reference a 4.4" MIP uses around 5mW)
At the very worst, SBC makers would have to allocate more empty PCB space to fit a form factor, when they could get by making a smaller one (or at least having to pay for developing 2 form factors, one "universal.")
Yet, it wouldn't be as embarrassing as Walmart's $200 Linux PC in 2007, which used an embedded VIA C7 in a Mini-ITX motherboard, in a Mid-ATX case, to keep up the appearance of face. https://www.wired.com/2007/10/200-everex-gree/ (And there isn't really anything wrong with having an ITX in a full-ATX either, esp if installing a 3-slot RTX 4090.
At best, more users might be willing to buy a universal form factor because they could easily adapt it to components they already have.
Of course, I'm only addressing a very specific issue/request, and it isn't suggesting that technology is going to solve everything. There is a book written on the OLPC that already addresses its failures "The Charisma Machine". In my opinion, though, a computer is a tool that can serve more as an appliance than a service, much like TI-Solar calculators were useful tools. Software as a Service and Apple (Hardware as a Service), are not always practical solutions, because not everyone can afford the security updates (and sometimes, the application might not even require it, like a public kiosk for general information). I think computers reaching their "end-of-life" have a utility at the very least, as an offline encyclopedia, and e-library.