Perhaps this question was asked earlier (I didn't go through all the posts):
What capacity does GM (incl. suppliers) have for producing batteries? It seems to me a "Gigafactory" of sorts will be needed for several (if not all) suppliers to meet global EV demand?
LG Chem is the supplier of batteries for GM and a number of other car makers. According to various news stories, LG Chem has the capacity to provide batteries for 50,000 Bolts max.
At this moment, most battery makers have unused capacity because worldwide demand for EVs is not high enough, except Panasonic who makes batteries for Tesla. Production of EVs is still quite small. insideevs tracks sales and last year 550,000 EVs and PHEVs were sold worldwide. About 100 million cars and light trucks were sold. That's less than 1/2% of all car sales, and most of those cars have very small batteries.
To build all 100 million cars and light trucks as long range EVs would require the equivalent of 200 Gigafactories and cost about $1-$2 trillion USD. Even with the low volume of production, demand is still quite low too. For most EVs, they are currently customer constrained, for Tesla they are currently price constrained. The rate of reservations for the Model 3 is an indication that it could prove to be the game changer that makes EVs popular. It looks likely the Model 3 will be production constrained for the first couple of years of production at least.
Car makers are largely followers. If a company makes some kind of move that proves popular, suddenly everyone jumps on board. They have been able to dismiss Tesla because they have been rich kid toys up to this point. They dominate the top end sedan sales, but that's a tiny market most car makers can afford to ignore.
If someone makes a product that proves to be popular with the mainstream of car buyers, then they all scramble to catch up. I was in high school when Chrysler introduced the mini-van and within a couple of years most car makers had a mini-van. SUVs have been around for a long time. International Harvester made one back in the 70s and Jeep was pretty much built around that kind of vehicle. Chevy had the Suburban and there were others, but they were always niche vehicles. When the mini-van fad died down, a lot of those buyers moved on to SUVs and that became a boom market with some extreme examples like Hummers.
Accessories run in fads too. Low profile tires have become a fad that most car makers, even Tesla, are all ga-ga about right now. They are very impractical compared to what tires used to be, but it's the fashion. Glass roofs, moonroofs, sunroofs, etc. are also a fad that is booming right now.
If the Model 3 proves to be as popular as it looks like it will be, long range BEVs will become the next new thing and everyone will be scrambling to make enough BEVs. However Tesla will be the only company with enough battery manufacturing capacity. Other companies will start crash programs to build battery factories, but there will be about a 3 years delay where demand will outstrip supply by a large margin and that will be the point where some car companies will probably fold. They won't be able to survive the drought that happens when the buying public sits on their wallets waiting in line for a BEV rather than settle for a new ICE and will keep driving their old ICE a little longer.