Having $10 billion in cash sounds like a lot. But that's against the $500 billion car companies will be investing this decade: https://www.reuters.com/business/autos-transportation/exclus...
It's also not much compared to the $130 billion Tesla's top 10 investors have lost on Telsa since the Twitter takeover started: https://www.investors.com/etfs-and-funds/sectors/tesla-stock...
And Tesla is coming under pressure to spend their cash not on investments, but on stock buybacks: https://markets.businessinsider.com/news/stocks/tesla-stock-...
As to the future, we'll see, but it's perfectly possible that Tesla will end up in the bucket with Groupon: promising early start, but in retrospect only of historical interest.