It's worth pondering when people do things unintended within the constraints of the original instruments. All the best Tex-Mex players are going beyond their instrument. Only a few have jumped to CBA, Oscar Hernandez most famously. There's vid of him on CBA duelling with Joel Guzman on 3-row diatonic. Not a fair fight. I saw Guzman demonstrating chromatic runs on a 3-row box, "We didn't know you weren't supposed to be able to do it, so we did." Maybe the difficulty becomes part of the art?
(Not a great quality video)
Joel Guzman and Oskar Hernandez performing Cuatro Milpas at the Narciso Martinez Conjunto Festival in September of 2004https://youtu.be/ncByWFsecqw
Seems like a lot of virtuosic diatonic playing is based on getting beyond the diatonic's limitations.