They were first because no one else tried. It's that simple. Companies have been dicking around for decades with the hybrids, electric assist, alternate fuels, etc., and no one went whole hog before Tesla. Then* every auto maker on the planet started rushing to catch up.

Even if you discount Tesla's early lead and fast forward to 2017 when the Model 3 went on sale and GM was offering what appeared to be real competition in the Bolt, by 2021 Tesla has sold over a million 3's to GM's 100,000. And then GM had to recall all the bolts it had ever sold because they kept catching fire.

2019 is the same story with the Ford Mustang EV. Pretty decent, no real problems (other than their glass roof flying off sometimes...) but the model Y out sells it by hundreds of thousands, even beating Toyota one year for most sold globally. It's the second best selling EV SUV behind the model Y. Ford sold something like 10K of them in Q3 2023. Tesla sold over 400,000 Model Y's and 3's that same quarter.

The other car companies in the US at least just aren't putting in the effort to match those numbers. They don't want to put their money on the line.