Gas stations make about 10 cents per gallon gross profit on the gas pumped. That's before capital equipment depreciation, equipment maintenance, facilities staff, cleaning, etc.
It's profitable, but it produces a minority of the business's profit. The bulk of the profit is from higher margin snacks, drinks, alcohol, cigarettes, lottery, etc.
A switch from gas to electric is not going to affect most convenience stores.
According to 7-11, 39.75 cents per gallon in first half of 2022. Also, while same-store merch sales grew 4.9% y-o-y, gas gallons sold grew 44%. (page 25 of the link)
https://issuu.com/avantimag/docs/avanti_sept_oct_2022_final
> 7-11 and Wawa have been serving gas since as long as I can remember.
You must be young, Wawa was not traditionally a gas station. It opened its first store in 1964 and had over 500 by 1992, but the first with gas was in 1996.
7-11's history and relationship with gas is more complex, but most legacy stores were freestanding store only (no gas).
https://www.burlingtoncountytimes.com/story/business/2014/04...
Selling gas is hugely profitable, labor cost for dispensing gas is zero. It's why legacy c-store operators like 7-11 and Wawa now include gas at almost all new locations they build.