The midfield/privateer teams like Sauber, Williams and Force India would stand to lose the most should 3-car teams be allowed. Running 3 cars requires enormous expenditure beyond the reach of all but the best-funded teams (the aforementioned “Big Three”). With more competitive cars on the grid, the midfield teams are indirectly demoted in the running order.
Suppose the scenario you mentioned were to occur – Ferrari, running 3 cars, finished 1st, 2nd and 3rd in a race. Suppose a Sauber driver finished 4th.
- Only the top two results per team are counted, so Ferrari gets points for 1st and 2nd.
- Yet the Sauber driver only receives in points for 4th place, rather than the 3rd place he technically finished in when the lowest-ranked Ferrari is excluded. If you factor in the other 3-car teams, the midfield teams get bumped down further and further, receiving less points than they would score otherwise.
- The Ferrari driver who finished 3rd walks away empty handed. Thus the 4th placed driver scores more points than the one who finished 3rd? Counting only the top two finishers punishes the team’s third driver, so why have him in the first place?
Overall, it opens up a can of worms that affects the complexions of both championships.
Realistically, 3-car teams will never happen. Most frontrunning teams (except maybe Ferrari, who seem to be the only ones interested in it) would rather use the expenses of a third car for research and development. Midfield teams not able to run 3 cars would veto the idea as they lose out in the points standings.