If I didn't know, that I had to wreck myself after all other drivers are wrecked, I would have sat there waiting. Exactly as you did. Here is a tutorial for your next tutorial: Show the thing you wanna show from the beginning to the end, and with all necessary steps in between.
It's easier and more profitable to just wreck yourself out with a lawn mower. You take 2 people out and hit the wall and you get 8,000 xp and $3000 in less then 10 seconds.
I prefer just doing a 2 minute deathmatch derby. AI all get mowers just make sure you get number 1. Nets about 2.5k credits. Rinse and repeat. It is also more fun.