Good question.
Answer is: Not much. It was a game back then, not a business. Neither owners nor drivers were in it for the big money because there wasn't any. There was no TV, and when TV did come in it was extremely limited for some years, meaning no advertising income. (Also not much fame for the drivers.) Certainly not enough money or fame to pay for today's closed "safe" tracks, and so Grand Prix racing was conducted mostly on public roads. No particular prestige attached to the sport itself, and its "stars," who were unknown ten feet away, died fast, which meant there were no distant, sometimes inor countries clamoring for a race of their own at any price, all of them willing to pour in money, wanting to join the big boys, wanting to touch imagined, international greatness, wanting the avalanche of international advertising and publicity. And so there were only seven or eight races a year, not 25. Small things could have been done, but nobody had thought of the wide tires and other technical gimmicks which, when they did come in, did not at first slow the dying very much. And the drivers themselves rejected seat belts. They thought that driving race cars on public roads was safer without, fearing they would not be able to get out of the wreck and would burn to death. And so it went. What I saw, wrote about and to a large extent lived with, bears no resemblance to the sport today. I'm glad that I was there then, and so close, and if Grand Prix racing was to be what it was, that I got to see it and write about it, and be appalled by it. It was a small brilliant world. I regret it's passing. The much bigger world is richer because it once existed, and if it were possible I might vote to bring it back. Would I really? I don't know.