'Electric cars for everyone! Woohoo!'
^^ that's the exciting bit, right?
However, you don't get there without Tesla. Why not?
Because you can't compete with low-margin products in a low-margin industry, and still innovate in a sector where you need lots of R&D, where component costs are currently expensive but are expected to drop over time, etc.
Even the much-celebrated entry, at scale, of other manufacturers into the electric-car market is due to Tesla.
Tesla is kinda like Apple in this. They built a very adventurous, dangerously new, premium product, and really committed to it (think mac/iphone; like Tesla, it's not like there weren't other similar products/concepts, but a good consumer product hadn't existed). Upon market validation of the concept, other people jumped in (windowed PCs with initially non-clipping windows; initially crappy android phones).
The reason this is exciting? Because: 'electric cars for everyone! woohoo!'
IT'S VALIDATED THE MARKET! They've waded into a real, big industry, taken on incredibly ambitious problems ('start a car company', 'make an electric car'), and in the process created demand for a new premium product, something the market 'didn't know it wanted'.
Without Tesla demonstrating that there's a premium market segment here to be targeted -- essentially doing market research for larger companies -- we don't get there as fast.
Other people invented (windowed desktops|electric cars). But without (Mac|Tesla) productizing it successfully, how many years would it be before the consumer enjoyed (windowed OS'|electric cars)?