Tesla isn't some start up that just IPO'd, it's one of the world's largest companies. Very few companies manage to double revenue in 3 years.
So you might next claim that revenue only doubled but stock price 10x'd over that time period. Well the reason is pretty simple, an investor who buys Tesla before its revenue grows will enjoy a better return on their investment compared to an investor who waits until afterwards to invest.
When investing, you want to look to the future potential of the company, not its past. If every 3 years Tesla manages to double their revenue, then after 6 years Tesla's revenue will match what you think is a reflection of today's stock price. At that point it will be too late to capitalize off of Tesla's stock price.
So either Tesla fails to continue its growth, maybe people end up losing interest in electric vehicles and other projects Tesla is working on, or maybe its competitors manage to produce a better electric vehicle and end up with superior battery technology... or Tesla will continue to dominate this sector, will continue innovating in this area, and in so doing will capture new segments of the electric vehicle economy that very few people are able to appreciate today.
The stock market is risky business, no one has a crystal ball, but the market is indicating that electric vehicles are going to be the future, and Tesla is the dominant player in this emerging market.
Based on what?
Employees? 70K is not even on the chart. (Top 10? 500K+)
Revenue? $31.5B is also not even on the chart. (Top 50? $130B+)
Profit? $800M, again, not even on the chart. (Top 10? $24B).
Market cap? This is the only area where Tesla broaches the top ten, and it has nothing to do with being a "large" company.
Also maybe you personally wouldn't be surprised if BRK didn't double revenue over three years, but people who are in the financial space would be absolutely shocked if it did so, considering the last time BRK managed to double it's revenue over a three year period was from 1988 to 1991.
Share price is a whole other discussion, of course.