Why are we acting like they're the only one that makes mini-ITX stuff?
Who is saying that? Not the comment you replied to:
... you can use their motherboard in other cases if you care about the power supply being non-standard, or other motherboards in their case if you care about the soldered RAM.
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Or I could just buy a mini-ITX motherboard, CPU, RAM, and mini-ITX chassis and not have to throw away any of their crap that isn't suitable.
Right now, this looks like it should be one of the most powerful mini-ITX boards that I can find on the market. I suspect MINISFORUM and others will have similar boards available soon, but right now they don't.
The whole point of Framework is that they make it very easy to buy exactly the parts you need. If you want specific parts, they will be available in the marketplace later in the year, and you can buy exactly which ones you want. If you don't want any of their parts, you're clearly not the target market.
The first I ever saw measuring in liters was the rise of the "1-liter PC" like the aforementioned Lenovo ThinkCentre "Tiny" series, the HP Elite "Mini" series, the Dell Optiplex "Micro" series, the Intel "NUC" series, etc. ServeTheHome has a great series of articles about this form factor, which they call "Project TinyMiniMicro".
Companies have been specifying chassis volume in liters for smaller desktop PCs for many years (doing a quick search found references 10 years ago), since it's an easy way to compare the size of all small form-factor (SFF) PCs, not just the tiny ones described above. But I think it's become more popular along with TinyMiniMicro-type projects, since mid-2020.
I was disappointed to see the soldered RAM, but the fact that it's a standard mini-ITX form factor means that you can use their motherboard in other cases if you care about the power supply being non-standard, or other motherboards in their case if you care about the soldered RAM.
Most of the desktops that I use these days are the "1 liter" PCs, such as the Lenovo ThinkCentre Tiny, but those are 100% proprietary parts other than the RAM and SSD. If I had a place where I needed a more powerful system and wasn't space limited, I would probably consider this machine.
2 pints = 1 Cavort