Not sure how you got one that gets 55mpg, mine gets 44 (47 was on the sticker). But in CA this still beats 100% EV.

You really do have to do the math using your local costs. I'm in a place with slightly cheaper gas but much cheaper electricity than California. Combined with cheap night time electricity I'm paying under $0.03 per mile for a large EV. I would need 150 mpg vehicle (assuming $4.50 gas) to beat that. However I'm cheating a bit - I'm on a plan which raises my day time electric costs a small amount in exchange for half-price at night, so they're getting some of that back, and I should amortize charger and electrician work ($1600 for me).

Yeesh. I get 44 mpg in a much heavier Toyota hybrid. But it probably depends on what percentage of your driving is in the city, vs highway.