I have a non-Tesla EV and the Ford and Rivian trucks that have now hit the market have ruined public charging. As you say, they hog the space for literally hours when everyone else needs 20mins. I finally gave in and purchased a home charger despite still having a special deal on free public charging.
In an efficient world, charging costs would have significant time factor to account for opportunity costs. The supercharger network already charges an idle fee if the charger is busy and you don't leave your space when fully charged. The same idea could apply for charging slowly.
