that's not really a good summary of what MoEs are. you can more consider it like sublayers that get routed through (like how the brain only lights up certain pathways) rather than actual separate models.
I'm not saying it is a perfect analogy, but it is by far the most familiar one for people to describe what sparse activation means. I'm no big fan of over-reliance on biological metaphor in this field, but I think this is skewing a bit on the pedantic side.
re: your second comment about pruning, not to get in the weeds but I think there have been a few unique cases where people did lose some of their brain and the brain essentially routed around it.