Tesla has already lost marketshare in almost every market so they won't be bigger than Ford in 2 years. They will likely lose their regulatory credits some time this year because VW, Audi, Porsche and Ford have strong offerings.
Examples: IBM with IBM PC, Apple with iPhone.
And we all know how many IBM PCs IBM has sold over the past decade.
I think that IBM might actually be the most apt analogy for Tesla. 20 years from now Tesla will be a niche player in the market they built basically from scratch.
All that being said, I'm far from confident enough in this prediction be to be actively betting against Tesla.
If Tesla goes out of business and sells itself to an Asian automaker when EVs have completely conquered the transportation landscape, I'll be OK with that :)
But all these EV sales come at the expense of gas/diesel sales, so I think it is a bad idea to consider EV's as a separate market.
It's unrealistic to expect that Tesla would continue to dominate the EV market forever. It is realistic to expect that Tesla will become a significant player in car sales globally.
How could Tesla become a significant player in the overall market without being much more significant in the EV market, which is a small subset of the former?
Eventually, virtually all vehicle sales will be electric. This will happen faster in some regions than in others.
How can Tesla be a significant player in car sales globally, when as a percentage of EV car sales, they are decreasing?
Think about it for a second and it will come to you. As more cars turn EV, unless Tesla maintains their marketshare, they will become less and less significant. They've lost marketshare in the first year that the major car companies have introduced reasonable EVs. Their 2nd derivative is negative.
Tesla is valued at 3X Toyota with having a fraction of the sales. What happens when the EV market becomes fully realized, but Tesla isn't the market leader but a small player. Do they still deserve to be 3X Toyota's market cap?
No, that's not neccessarily true at all.
Let's imagine that in 2021, EVs are 2% of car sales globally, and Tesla has 50% of the EV market. That means that Tesla has 1% share of the entire car market.
Now imagine that in 2031, EVs are 50% of car sales globally. And Tesla's share of the EV market has "shrunk" to 20%. But that's still 10% of the entire car market. Even assuming no market growth, that's an enormous 10X (1000%!) sales growth for Tesla over 10 years!
Even though its share of the EV market has shrunk, Tesla is selling 10X more cars and is a far more significant company in 2031.