That they didn't do this is rather unfortunate, because it should in theory be quite possible. Heck given recent advances in small parameter models, it might even be possible to run locally with some custom HW.
A voice only interface capable of running any android app would be pretty cool. I doubt Google will ever release that (I'd love to be proved wrong) if simply because it risks destroying the display ads market.
EDIT: it's found a home!
What big tech companies? Rabbit doesn't have any competition.
I got one as a gift - been trying to sell it unsuccessfully for months now…