I’m confused.
The only tracks (5 and 6) in the linked graphic that have a stereo wave file are both Real Drum tracks. *
And that makes sense. A drum kit is made up of more than one thing. One could have the kick and hi-hat in the left channel and the snare and cymbal over on the right.
But a saxophone or a guitar etc. is only one thing. The sound is only coming out of one place. How does one record a sax in stereo.
The instruments themselves are mono.
When imported into a DAW, though, one can then have the choice to import in stereo or mono.
I import in mono and then pan 25 to 50% to one side or the other to get a stereo effect.


* Having two drum tracks that’s a cool idea. Worked great for the Grateful Dead and The Allman Brothers.