Often. Maybe F1 drivers should be like horses in a claiming race. The top three drivers in each race can be bought by another team. That would keep them moving around and we'd begin to see when the driver makes the difference and when the car does. All the drivers would be on base salaries set by FIA, all money over that would be for promotional services and paid directly by sponsors to the drivers. Those worth a lot would make a lot, those at the other end of the stick would only get what the market felt they were worth. The cream would rise to the top, and the dregs would get thrown out.