Wow yeah BYD went to the Moon in the final quarters, which I hadn't checked! Somehow I suspect this article wasn't talking about China though, which is clearly where Tesla really needs to step it up!
Heaps of BYD EVs on the road here in Australia, and Tesla sales are plummeting here now too.
Tesla's also a relatively small part of the market in the EU (varies, but generally on the order of 15-20% of the BEV market). The US is really the only large market where they're very dominant, and (and this should be concerning for them), it is the least _mature_ of the three big markets; many EVs were not launched in the US at all, and most of those which were were designed more for European or Asian tastes than for American (the Nissan Leaf, say, was available in the US, but is not the sort of car which sells well in the US). As that changes, and more EVs with good product market fit show up in the US, you'd expect the US market to evolve more towards the European one (that is, a bunch of manufacturers with 5-25% market shares). That's what normal mature markets for virtually everything, and certainly for cars, look like.