https://www.netonnet.se/art/ljud-och-bild/kablar/hdmi-kablar...
Or there were no cheap enough stacked port.
So it's not rated for 4k, but it will support all the DRM stuff.
I used to lose the Micro to C adapters all the time, I lost the C to headphone for my OnePlus6T while travelling and was unable to find a replacement so no headphone use for me.
Also, I have about 12 Raspberry Pis, as many display devices, a dozen or so other HDMI devices such as consoles etc, and tens of normal sized HDMI cables lying around and they're all compatible.
If I remember correctly (and that's a big if), DisplayPort started royalty-free but then they introduced royalties. From my blurry memory: I checked once many years ago and it was free, but then I checked again a couple of years later and it wasn't exactly free any more. Did it change again? Or am I completely wrong from the start? If someone remembers the history better than I do...
More common in monitors perhaps, but I don't think I've ever seen a TV with a DP input. Since AFAIK the target market of the RPi is "plug it into a TV, plug a cheap USB keyboard and USB mouse, and you have a working computer", having HDMI output is a requirement.