These days, it's hard to take anything for face value in the media. It would be interesting to dig into the actual data from Hertz to know the full truth.
Modern ICE cars are basically maintenance free for the first 100K miles, except for an annual oil change. Gone are the days of greasing 25 Zerk fittings on the chassis every 6 month, cleaning ignition points every year, changing coolant every 2 years, doing engine oil changes every 3 months, spark plugs every 15K miles, transmission and diff fluid every 30K miles, etc...
So between an electric car and an ICE, it's just an oil change saved. And the Model 3/Y have a nasty habit of needing a cabin filter with an expensive anti-bacterial treatment every 6 months, which costs as much as an oil change and takes even more effort than an oil change.
In the article, the tire thing is brushed off without giving any hard data, but I bet it's a bigger differential cost than they are making it out to be. It doesn't take a lot of research to find out that the correct tires for a Tesla are double the cost of what's available for ICE cars, and that they are often wearing out twice as fast.
And I bet their windshield replacement costs are much, much higher due to Tesla's forcing people to get the glass from them, which is probably not insignificant category of cost for a car rental company, but doesn't make it into these "maintenance" costs.