It may be true that when 30% of vehicles are EVs, oil change locations will be hard to find, but I doubt it. Even if dedicated oil change chains cease to exist, people will still need tires, alignment, etc, and those shops will presumably provide oil change services.

Regardless, it's going to be a while before 30% of vehicles on the road are EVs — isn't it like 1-2% of new cars sold? If vehicles stay on the road for 20 years, then EVs won't be 30% of the total fleet for a long time.