It's alright - I didn't take you as being rude, but you are grossly misinformed, sadly :-)
You can't just make any random USB hub "15v ready". There's no such thing. This is actually an USB-PD-enabled hub. Those are super rare and hard to get right now, and have to abide very strict specifications. For more details, see:
https://en.wikipedia.org/wiki/USB#Power_Delivery_.28PD.29
A regular USB hub will limit power to 5V as voltage, and most of them also correctly limit the amperage to 0.5 amps (technically the maximum allowed per port for regular USB 2.0, which is what most hubs are). This means the Switch would charge at a really low rate and take many hours to fully charge. Most likely they only enable the HDMI output when there's enough power to sustain it, probably meaning 15 volts. (Though the switch can handle all USB-PD voltages <= 15V, and it's possible a lower voltage is enough as well. I don't know if anyone tested this yet.)
A USB-PD HUB needs to be able to convert voltages and negotiate them. After all, only one voltage can go through a USB cable simultaneously, so it's the hubs task to convert the 15V to 5V for regular USB2. Keep in mind there's also an USB3 port in there, which can draw up to 0.9 amps, possibly more if it also support USB-PD, which it probably does.
Following your own teardown source, you'll see one of the chips in the dock is a VL210. Specs for that are here:
http://www.via-labs.com/product_show.php?id=56
You'll see this chip can actually convert voltages and trigger various USB3 charging modes. So yes, there *is* something of interest there, as that is not just any USB chip but a really nice one.
A close match is this device, which contains the same charging chip:
https://www.amazon.co.uk/Digitus-70838-Type-Adapter-Chipset-VL210-Silver/dp/B01LXLR9MC?SubscriptionId=AKIAILSHYYTFIVPWUY6Q&tag=duc08-21&linkCode=xm2&camp=2025&creative=165953&creativeASIN=B01LXLR9MC (in fact, it's quite likely that this device combined with the official nintendo charger will actually output HDMI... would be interesting if somebody could test this...)
That's a $55 USD device. And it doesn't come with a 15V-enabled power supply, which you need to get separately. Good luck finding one cheaper than the one Nintendo offers. Later some will surely show up, but right now? A charger made by Anker which costs $45 seems to be the closest match.
So, yeah. Please check your facts before you accuse me of talking nonsense. I realize I didn't cite any sources in my first post, but that doesn't mean the information is wrong! As you are a gbatemp reporter, I frankly expected a bit more from you to be honest.