Why still USB 2.0?

No reason to go higher.  USB 2.0 has plenty of bandwidth for audio, including DSD.

USB 2.0 has the widest compatibility as well.

To give you an example, a 384kHz/32 bit stereo audio signal only needs ~ 25 Mbps but USB 2.0 supports 480 Mbps

In addition, USB 3 cables require a lot more wires (conductors).  This means the quality of individual conductors will suffer.

Plenty is right, get over it.

Plenty of people in the "more is ALWAYS better" camp. Doesn't surprise me in the least that some think having a transmission speed that is almost 1,800% higher than the max needed isn't good enough. 

Similar thing with formatting USB file systems for music etc.

I tend to prefer exFat because it outperforms the much older FAT32.

Yet FAT32 is the only one that most devices recognise.

Oh well, FAT32 seems to do the job well enough!

I guess if good enough is good enough, then what’s the point of unecessarily over engineering and risking yet another bout of audio nervosa?

I always try exFat first with a small sample.

I expect if USB 3.x was lower noise than 2.0 it would be in use.

usb3 is for 8k video

The high end audio industry is slow moving because it requires a lot of time and research with materials and designs to release something of superior sound. This takes time.