On the autonomous driving side, Waymo and other teams are years ahead of Tesla. Elon's been able to convince the market otherwise and so far they've bought it. In the next 1-2 years as self-driving cars get deployed onto the roads this will be undeniable.
I don't see a big, Theranos style implosion. The market will slowly grow concerned, there will be a "correction" which Tesla stans will ignore and then will be a slow decline with dips each time competitors release strong numbers. By 2023-2024, Tesla's market cap will have fallen 70-80% down to that of other car makers.
I suspect someone will release an actually affordable (comparable to ICE up front and ownership costs), safe, basic EV with decent range and standard car features which has better quality and less hype around it and Tesla will be lose the ass end of the model 3 market. It’ll all collapse from there.
Edit: to qualify this my father paid over £5000 for it three years ago.
I honestly don't think that Tesla is hiding fraud at that level. If anything is going to kill Tesla, it'll be cheaper, higher-quality competition, probably followed with lies about sales figures. Things that are years off (as far as I know.) Lies about what your technology is on the verge of doing are standard for the tech industry.