They don't offer an oil change though, I've never seen a wash+detail+oil change in the area. At scale I'd assume they could do it for closer to $50, if $35 was a 2005 price that's on par with inflation and beating inflation for some industries like food.
Oil changes require following environmental regs, careful disposal, paying for same and it makes a 1000x more sense to integrate them with a business that actually works on cars and can capture additional dollars for other maintenance and repair.
You also want a comparatively skilled and trustworthy individual not someone who moved up from vacuuming to oil changes and a business than can easily write a check if their employee does mess up your expensive asset rather than an owner who will have to decide between writing you that check and paying their rent and employees. This is also why you don't want to get your oil change at walmart.
If you could have it the oil change would have to cost $50-$60 to justify its existence because there would be no chance of capturing additional revenue. If it had full service and 2 people spent 15 minutes we are talking about another $30. This is only true if you can actually keep relatively busy and aren't implicitly bearing the cost of labor while people are waiting for customers.
Then there is competition from both auto repair who are offering 29.99 oil changes and 5-9.99 automated car washes.
Growing up in the West and Midwest, these things were absolutely normal for the first 30 years of my life. Some of them would even change the oil too. But I haven't found anywhere within 50 miles of me that will do it here. I'm not talking "detailing." This was $35 including the oil.