Then saying and labelling it on top of a socket as I2S is plain wrong. Cables, connectors and buffers are not defined but the data happens to obey an inter IC protocol that was once designed by a manufacturer. It is not a standard it is "look what a concocted if you also concoct we may communicate". One may argue that this is how open standards develop, but that is not the case here. There is no agreement of buffers, cable type, sockets, etc. written down and agreed by more than one manufacturer. Everyone use a different method.
Once again: I2S is not a device to device connection standard. What we see on some devices are custom implementations of "a" protocol. Nobody should care nor rely on it.
Much too late; o)
There are thousands of satisfied users of i2s over LVDS worldwide. Alone the whole users of the digital USB converters from Gustard, Xingser, Audio GD etc., plus many streamers and DAP with this interface (and there are more and more).
In addition, there are now thousands of i2s -> HDMI (LVDS) and HDMI (LVDS) -> i2s modules from the DIY sector that have been sold. The number of available modules has increased tenfold in the last 2 years. There are also many special modules for individual solutions.
And yes, i2s is only intended for internal data transmission and is not used in any other way.
And LVDS is the standard that was developed precisely for such applications to enable external data transmission over short cable routes.
And LVDS is also the world's most common standard for this type of data transmission, both in industry and in computer technology and consumer electronics.
I understand from your signature that you should be familiar with the layer models. The LVDS standard works on the physical layer and therefore allows cable connections where only short connections via conductor paths are actually possible. These LVDS connections are "invisible" to the application and that is the trick. Therefore nothing else is required, not even buffers.
It should also be clear why the LVDS standard may not contain any specifications about cables or plugs, because it would then be unusable and superfluous.
With LVDS, audio manufacturers have chosen exactly the standard that was created to enable external transmission for standards such as i2s.
Over 95% of the devices on the market with this interface can be connected and operated with a standard HDMI 2.0 cable.
This is also no worse than USB 3.0 when it was first introduced, where, despite the extremely high level of standardization, there were problems with almost every second device at the beginning.