You are underestimating how much 12VO simplifies the PSU design and the number of things that can go wrong on a system. 12VO turns the PSU into glorified laptop power brick, and all the complexity of dealing with lower voltages goes to the motherboard. You won't need a seasonic PSU for stability if all it gives you is a single 12V line.
The reason you need "a quality power supply" is because loading the 12V power line, destabilizes the 3.3V and 5V and causes system problems.
If all you use throughout the system is 12V and all of it is behind a switching VRMs, you can brownout down to 8V and the system will still be standing and working normally. Any laptop power brick can handle that. In fact, there is a reason laptops never have problems with PSU stabilities. Its exactly because they are using a single voltage, and every power plane on the motherboard is behind a VRM. In fact, when laptops are switching between a power brick and the battery, the main voltage plane loses 2-3V, and the laptop is still ok.
With this change, the PSU quality discussion will go out the window. You will literally get 1200W platinum PSUs for 50-80$ instead of 250$.
You aren't getting rid of those other rails though, you are moving them to the motherboard. A motherboard of which will be more expensive and requires more frequent upgrades than a PSU. I only replace my PSU once every 10 or so years while I change my motherboard every 3. In essence you are increasing cost over time. In addition, you are pinning the quality of voltage regulation of the minor rails to the quality of the motherboard you buy, which is silly. Motherboard vendors have a financial incentive to get you to buy a more expensive motherboard, which could mean their "good" power designs are only on high end motherboards. This new ATX standard being new with few implementations also means that mistakes are far more likely as well.
The 12VO standard is straight up against the spirit of the PC platform as it removes a portion of the modularity of the ecosystem. No longer does swapping your PSU upgrade your system's power delivery and no longer is it relatively easy to diagnose potentially power related issues. It gurantees that anywith with system crashs during an intensive game cannot elimiate the PSU as a source of the issue by swapping it out and necessitates that you break out the multi-meter and then spend time looking at the board to find and measure it's voltage regulation circitry (which let's be honest the overwhelming majority of PC gamers cannot do). In essence you are making the PC platform significantly less user friendly.
Comparing laptop power issues to desktop power issues is sort of apples to oranges given you are talking about a world's difference in power consumption. Mind you I've seen more than my fair share of failed laptop power circuits. I've got one that failed for that very reason right on the desk next to me. The one thing they have in common is that they require an expert to repair them and they render the whole system inoperable. Compare that to a desktop where if something goes wrong with the PSU, the end user can take very simply concrete steps to figure out the issue themselves. Can you imagine how much ewaste would be eliminated if laptops have dedicated PSUs? A lot but that would cut into profits. Seems some people forget just how much harder it would make PCs to repair and just how much more ewaste it would create as a result.
And then you'd get like what? 1500$ motherboards? We already do.
MBs will always get more expensive, no doubt about that unfortunately.
The only motherboards we have in that price range are limited run extreme OC boards.
Everything will get more expensive due to inflation that naturally occurs over time, that goes without saying. That said, you missed his point if that's all you though he was saying. Aside from normal economic pressures, adding more parts to motherboards will increase the average price end users will pay for their motherboards, particularly on the low end where boards are already stripped to the bare minimum. Take any increase in price you had though was normal and push it significantly further.
I don't think this would increase motherboard prices so much that their cost would be the same as current mobo + PSU. If ATX12VO components are more expensive right now, it's not due to the added components but because they are produced in so low numbers.
Even if you assume it doesn't, you are still buying 2-3 motherboards in the lifespan of a single PSU. At the end of the day you are almost certainly paying more as you are buying those components moved to the motherboard 2-3 times instead of once. IMO that is not the biggest issue though, it's the reduction in repairability and modularity.
That is a trivial warranty replacement. We already have a system for it. Also, both motherboards and GPUs have 12V to 1.1V VRMs on them. That is what the VCORE, VSOC, and VDDR voltage planes are doing, taking 12V and turning them to local voltages. Now all that will happen is you will get VUSB and VSATA planes. That is it. And SATA is already on the way out. It will either go away completely, or turn to 12VO SATA.
As I said, laptops have been doing this for decades, and we have never had problems with voltages popping. The only thing that gets damaged in laptops is the power plug, but that is just from repeated removal and insertion, not electrical damage.
You say trivial but replacing a motherboard is significantly more hassle for an end user than replacing a PSU. With a motherboard you are taking the entire system apart and then putting it back together. A PSU just requires you to take out the PSU. It's also cheaper to buy a temp PSU if you don't have on already.
Yes, GPUs have their own power regulation for local votlages. That makes sense, each device should be containerized as much as possible to ensure repairabily and modularity.
Now sure why you keep bringing up laptops are a great example of why power regulation shouldn't be integrated on the motherboard as explained above. There's a reason laptops don't last as long as desktops.
Says who? B350>450>550 had limited price inflation(?) if any at all.
I think he was implying that as a result of inflation, technically everything gets more expensive over time. That said I cannot really understand why one would say that because it misses the point. The person he was replying to clearly meant that motherboards will get more expensive as an additional cost besides any other market forces. That's would be what most normal people would assume in the context of adding parts to something.