Acoustic instruments rely on their size and shape for their acoustic properties. Reduce the size and you reduce the volume or alter the sound.

Most electronic instruments, on the other hand, have become smaller than their acoustic counterparts. Drumkits, keyboards, guitars, violins, just to name a few. While acoustic properties still matter in many electrical instruments, they’re not as important as before. I’ve seen an electronic cello that was pretty much just a plank with strings.