Years ago, I read a book that categorized the development of consumer products in a three-phase evolution:
Phase 1 - Small firms serving whatever they could shove out to market in a scattershot way. Think of the early 1900s automakers who made 30 cars each before closing or merging away.
Phase 2 - Volume scale products are established which rolls over much of the market with economies of scale and price-first design. The Ford Model T is the canonical example.
Phase 3 - Brands get established to target different consumer niches rather than direct price competition. Think of the golden era of GM where there was more or less a clear market segment and message behind Pontiac vs. Chevrolet vs. Buick.
I think many investors see EVs as a "Phase 1" product-- they're willing to bite on hype and random bad ideas, because they expect someone is going to execute big to become the Phase 2 market leader, or even end up as a focused, high-margin Phase 3 brand. We don't know who that is now, so bet on everyone!
On the other hand, there's an equally compelling argument that EVs are less a new market and more a variant of the overall automotive business that's already reached "Phase 3". Existing brands know their places and markets already, so there may not be that much realignment as they replace fuel tanks with batteries.
Tesla has proven it's possible to muscle into the market, but a lot of that was by identifying an unserved niche (the luxury consumer-covetable EV, instead of the minimal-for-legal compliance EV intended to sell to government fleets) which provided enough volume and high-margin sales to bootstrap their play. They couldn't have competed by trying to sell the Model 3 in 2012.