Oh it was reckless. That was the era when built quality was rock bottom. People were getting cars that were missing parts, or where things were attached completely wrong.[1] He was expanding production so fast that it caused a serious liquidity crunch at Tesla. But he got lucky and managed to squeeze through the problem.
Unless there's something the article totally omitted, your original retelling of the story was heavily misleading. For one, it's not a bet and is seemingly actually a performance bonus, which nearly every F500 company has for their executives. As such, there was very little downside if he lost the bet. It's also unclear why CEOs trying to hit aggressive performance targets is a bad thing in and of itself. You could still object to it on the basis of bad working conditions for workers, or corners cut on the product being made, but you mentioned none of that in your original comment, which seems to imply you were fine with all of those things, and was only upset that Musk didn't share in the rewards (???).
I will have to look harder to find the name of the investor whom Elon made the production bet against, but I think this article is talking about it: https://www.reuters.com/business/autos-transportation/teslas...
[1] https://www.cnbc.com/2019/07/15/tesla-workers-in-ga4-tent-de...