If one thinks that Tesla has 1 in 3 chance of becoming as big as one of the mainstream brands, it doesn't mean they'll be worth $200B. I don't think anyone would deny that Honda has been hugely successful and they don't even merit $75B as a wonderfully profitable company (rather than a company that just has potential). Mazda is a mass-market manufacturer with some of the most appealing models out there and they're worth a measly $12B.
Tesla might grow to the size of other major car companies, but that doesn't mean they'll grow to the size of Toyota. It will be hard for Tesla to grow to the size of Mazda given the challenges of launching any new car company. Growing to the size of Mazda would mean increasing from 33,000 vehicles to 1.3M vehicles (growth of 3,900%). And even at that level of sales, we see a company worth only $12B and I don't think anyone in the auto industry looks at Mazda as a company with worthless cars. In fact, Car and Driver ranks the Mazda 3, Mazda 6, MX-5, and Mazda CX-5 as the best in their categories.
I know that it's tempting to look at WhatsApp and compare. Facebook's purchases may be more about defending its control over social than anything else.
If you're thinking about buying an automotive firm (even if you think the future is electric), would Tesla be what you want to buy at $75B? It's unprofitable now with low volume and an unproven capability to scale to millions of vehicles per year. Musk is daring and willing to tackle hard problems like electric charging stations. But for $75B, you could buy Mazda, Subaru, and Fiat Chrysler (all three for $57B, granted buyouts usually involve paying a premium of 20% or so, but a 30% premium would be $74B). Does Tesla have a durable head-start advantage in electric vehicles that vastly outweighs all the things Mazda has going for it including profitability, vehicles that the auto press love, volume manufacturing around the world, sales and service to support millions of customers per year, etc.? Or are long-range electric vehicles a matter of commitment and willingness to lose money for a while?
Comparing Tesla to Toyota would be like comparing a new entrant to mobile phones to Apple. It's a poor comparison. Comparing a new entrant to mobile phones to HTC might make more sense. Similarly, even if Tesla is quite successful, becoming a Mazda, a Hyundai, a Subaru, or a Honda would be an amazing accomplishment. I think it's much more likely that GM would be worth $200B in the future than Tesla. That isn't to knock Tesla, but merely to acknowledge the reality that GM is already selling nearly 10M vehicles per year while Tesla would be experiencing phenomenal growth if they sold 100k (or 1%) of the number of vehicles. It seems much more likely that GM will increase the appeal of its vehicles, increase its margins, and gain the profits needed to match Toyota's valuation. It's hard to grow that much. I mean, Mazda has some amazing cars, but I don't think that's anywhere near enough to unseat Honda nevermind Toyota.
If you think that electric vehicles are the future and that the major manufacturers won't be able to compete with Tesla in electric vehicles, maybe Tesla sells 40M vehicles per year while they all end up selling tiny scraps. That seems unlikely to me. Tesla's patent trove is open for others to use which means there isn't much of a barrier for others to come along.
Again, none of this is meant to disparage Tesla. It's merely to note that Tesla would have to have phenomenal growth to become even Mazda's size in sales, something that is simply hard to accomplish. Even if Tesla ends up selling 10M vehicles per year (303x their current sales), GM does that and doesn't have anywhere near Toyota's valuation. That doesn't mean that Tesla isn't pushing the industry forward, it doesn't mean that Tesla isn't showing us that electric vehicles can be practical. It's simply to point out that it's very hard to scale up that much, I think there are genuine questions as to whether Tesla has any durable advantage long-term, and the reality that most auto manufacturers that are profitable and way larger than Tesla are worth a lot less than $75B.