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Yeah - and chainrings perhaps. You could design it so that you just buy a new cage (a few quid if we're optimistic?) and jockey wheels.
But yes, nothing in it for them; in fact they're way better off if you have to buy a whole new groupset for every bike that you want to switch from 10- to 11-speed. It would be really nice for gravel/CX/touring/commuter stuff to have electronic MTB/road mashup groupsets but I guess that's not a big enough market
Probs a different (narrower) chain though so software would have to know that, plus swapping the jockey wheels. When there are only two mainstream manufacturers in the industry, what's in it for them?