Thanks to the ULEZ (ultra-low emission zone) in London, this is very much already happening — anecdotally (because I can't find any easy numbers right now, everything I can find is from 2020) a huge number of the private and public taxis in London are now hybrid or full electric.

Apparently there are already 5k TX electric taxis out there, which is a good start:

https://levc.com/levc-celebrates-sale-of-5000th-tx-electric-...

https://levc.com/tx-taxi/overview/