Interesting claim. Complete parts list please!
Every time I've seen a comment like this, the eventual parts list is about the same price, has large deviations, or re-uses existing hardware (or used hardware). Looking at all the subreddits, the general consensus seems to be the price is fine for the components, and (if you care) it's impossible to build anything with that form factor.
It will be difficult to build it that small, however you will end up with a PC that doesn’t use proprietary hardware and is easier to repair. There is something to say about that.
You misunderstood my last sentence, and my overall point, so I'll try again: Do you have parts list that supports your claim, with all new parts, without caring about the form factor?