Why would they continue to decline? If all that information is already known, why isn't it priced in and why isn't the best estimate of Tesla's price in 6 months equal to today's price plus the return of Treasuries?
Tesla's current P/E ratio is 134. To be a rational Tesla investor, you'd have to think it has almost 600% profit growth potential to reach the long-term American blue-chip average P/E of ~20.
That kind of growth would be difficult for a new entrant, but for an incumbent that's been around a while and already seeing sales decline, it's a pipe dream. Of course, it's not all about cars for Tesla. They're betting big on humanoid robots and "full self-driving", although they've been stuck at Level-2 self-driving for years and the robots, well... Let's just say we don't hear much about them for a reason.
Of course, Tesla has never been a company for rational investors. I used to hold a lot of Tesla stock back in 2017-19 when they had plenty of doubters. I remember seeing how Tesla owners would organize themselves grass-roots-style to show off their cars and convince others to go electric. The company was getting a ton of free marketing and had a very devoted customer base. My, how things have changed. Now, they have to shut down showrooms across the country due to "terrorism".
So where is the upside? Well, protectionism could help them in the US market, but they're a global company with stagnant sales in the US, so it's hard to see tariffs helping more than they'd hurt. And that's pretty much it for upside AFAICT.