Sometimes you just have to "force" change.
A lot has changed in the cable and connector world for current transfer and connectivity. The problem with the current SATA power connectors? many of em. For once, you are not even using its voltage range by pinout anymore. This connector remains mostly to supply 12V today with 5V optional for the drives that need it (mechanical mostly).
I do agree this connector sucks btw, as much as I think the very old 4PIN one do. Im personally a fan of Molex' new Micro-fit 3.0 series, which can carry a lot of amperage and use small connectors. While im not a huge fan of the fact Molex will probably make money off of selling and lisencing it, any improvement is welcomed
ATX and MATX may not see too much from this, but MITX and some custom small form factor specific boards might really, really do.
How do you force change in a non cohesive industry? What if the motherboard makers and PSU makers say no?
The cost, without any direct user benefit (kind of like RGB LEDs) woll go up when it comes to motherboards and the PSU companies will have to offer cheaper PSUs, as they can't charge the same for a 12VO PSU, since it lacks about a quarter of the parts. Admittedly the 3.3 and 5V conversion parts are pretty much just a small PCB soldered to the power supplies these days, but still. This doesn't even take the case manufacturers into account and they've invested in their tooling that should last for a certain amount of units.
Maybe you don't remember that Intel tried BTX and it failed miserably, largely due to it being designed for OEM/ODM only and the fact that the CPU coolers weighed in at around a 1kg each at the time.
With regards to the SATA connector, you got that backwards, most spinning rust needs 12V whereas most SSDs only need 5V. The 3.3V addition is something of a mystery, as almost nothing used it.
Oh, the Molex power connector for drives was shite, but it was carried over from the AT standard and maybe even longer than that, but that would be before my time.
Some mini-ITX boards have been 12VO for years, but I have never seen matching PSU's, as they used a 4-pin connector, but also often an external connector that was wide range input.
It's not just about the space though, current connectors are wasteful for no good reason. They don't offer or need to offer a meaningful increase in current capacity, are bulky and require a lot of materials that could easily be reduced, not only without loosing functionality but actually increasing it.
But it is an industry wide standard that is going to take a lot of time and convincing to change and that's the core problem here.
It's very hard to make everyone agree on standards, even more so when it would require so many companies to change at a single point in time.
Motherboards should really have been improved a long time ago, but alas here we are using a standard from 1995...
27 years and the graphics card is still upside down.
This industry may be hard to change, but atleast Intel is making an effort, the same cannot be said of others since it would 'cost too much'. If there was to be large changes, there cant be backward compatibility, otherwise that reliance will not let the industry move forward. Adoption to new standards and designs wont pay off immediately and manufacturers will scream 'we profits now dammit!" and remain stuck with legacy and left in the dust.
It's not that efforts aren't being made, but the hard thing is to get an industry wide consensus.
Imagine if we change from ATX to say CTX (since BTX is taken), how many years do you recon it'll take for that to become the industry norm?
How many companies are there out there that want to have a say? In the bad old days, Intel could force new standards, which isn't remotely as easy for them today.
Just to get the major components manufacturers and OEM/ODMs to agree would take years. Just look at Dell, they can't even follow the standards that are out there.
There are going to have to be some serious compelling reasons to move to new standards.
Just to be clear, I'm not against change here, but it's going to take a serious amount of consolidated effort to make such a change and from what I can tell, there's no industry wide will to push for such a change and until that happens, we're stuff with an old, but still workable standard.
Personally I believe the shift will come when PCB traces have to change, due to high-speed interfaces no longer being able to use the ATX form factor. That might very well happen around PCIe 6.0 or whatever comes next after that.