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.
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.
What's the math on that? Average kWh in California is around 18 cents. Assuming 0.35 kWh per mile, that's 6.3 cents per mile. You'd need to get 100mpg+ to beat an EV at current gas prices. A brand new Corolla hybrid my family recently bought gets around 40-60 mpg driving around a small city. And that's without factoring in maintenance differences costs per mile.
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).