This is a massive UX issue. With gas cars you can use any gas station you want and you don't have to pay additional fees other than the gas.
I don't see what would really motivate businesses to change their mind on this. Since the barrier to entry for an EV charging station is many orders of magnitude lower than a gas station, it's pretty easy for a business to just add one in to an existing parking spot as an extra revenue stream or another way to draw customers. But they might reasonably value having available parking for customers over the revenue they get from EV charging.
I things will probably move more in this direction as EVs become more popular and the average customer is more likely to drive one.
I'm not sure what the state of the chargers being installed at local businesses is. My local grocery store has four chargers now, but I don't recall seeing any signage about them being for customers only. They share the parking lot with the church across the street, though, so that may complicate things.
IMO, the long-term tendency will be for every parking place to have an electric vehicle charger (or at least a standard power socket which can be used for a slow charge), the same way every parking place has electric lighting.