From my POV, it really should be up to the company and the market.
To use your example about charging networks, if a car company thinks it can make a charging network that is proprietary to its vehicles a selling point (to make up an example maybe because "we have the best locations, with the best amenities, they're super safe, and you never have to wait"), and invests a bunch of money to make that happen, builds out a great network that it uses to sell more cars, then having the government come in and say "your cars are too popular and are owned by an attractive demographic that other service stations want to sell to, so now you have to open up your charging network and allow your cars to charge at others' charging stations" would be out of line as well.
And if you bought that car knowing it only charged at company-owned charging stations, then that is completely on you. Buying it because "it's such a great car" and then complaining about having to use the charging stations even though the car company advertised "you can only charge at our charging stations" as a selling point, and its competitors ran ads saying "Don't buy it, you're locked into their charging stations, buy ours instead" would be ridiculous.