[bathurst77]

Another idea could be the current teams only but 3 car teams, with the 3rd car being a "juniors" car. totally different paint and sponsors to the main team, changing depending on whos in the car, with no single driver allowed to do more than 4 or 6 races a year in the car.

WCC points go only to your 2 best finishers each weekend.
(so if one of your main drivers has a shocker or DNF and your junior gets a top 10, the 3rd drivers points go towards WCC, but if all 3 cars re top 10 only the 2 best points count)

A youngster with budget to pay for a few races but not a whole year could buy a seat, plaster his stickers on the car, race a few selected events, then someone else next time. Or a team can give a "Lawson/Doohan" etc the car for a few races and a chance to show his stuff in the real world, without having to risk half of their whole years championship strategy.
Maybe only some races have facilities and pit enough for 3 car teams, so not every race has all 30.

For the teams they get cash from paid drivers, and a spare race-ready car at every track (Looking at YOU Mr V.) - Building 3 or 4 cars is not that much more expensive than 2 or 3. THe biggest cost is R&D testing, making the stamps etc.
They could even try new parts etc on car 3 and not risk the main game cars. More cars, more drivers, a way in for new faces etc, find the next Lewis/Max/Lando, lots of interest and lots for drive to survive to show.