I don't own Tesla directly, but I own some ARKK, which has TSLA as its largest holding. I picked ARKK up since it gives me exposure to some of these more risky companies without having to individually bet on which ones I think will win. I also find Cathie Wood's way of thinking about investing to be very insightful (she's the CEO of Ark Invest). Part of their reasoning for buying companies with high price tags like Tesla is because disruption happens slowly at first, and then very quickly.
Think about the cell phone market 15 years ago, and then think about it 5 years later. Blackberry, Nokia, and Microsoft used to be huge players in that space. However, when the iPhone debuted it changed things. Adoption was slow at first - and the bigger players theoretically had time to catch up - but they didn't. The companies that moved quickly and innovated took over the market. By the time Microsoft had a smartphone, nobody wanted it.
Ark sees Tesla the same way. They expect that in a few years time Tesla will take over the market and most of the other automakers won't be able to catch up - and even if they could, Tesla has a better brand name and will possibly be able to make EV cars cheaper since they've had a lot more time to optimize their pipeline. Additionally they may be able to lead the way in new markets like self-driving (especially self driving taxis - thus eating Uber's lunch).
I'm not completely sold on this, but it makes their valuation make a little more sense. I could see them becoming the biggest player in the EV market, and I wouldn't be surprised if most new cars were EVs in 3-5 years.