"Over" is too strong IMO. I believe Tesla still has a big advantage in the EV market in terms of actual EV output and charging network. And for anyone looking for long range/efficiency, Tesla is still at or near the top.
I do agree, though, that the combination of new competition and Tesla's poor quality/lack of new offerings/FSD issues is putting it on a downward trend. I also think Elon's twitter shenanigans could have an impact on demand since he seems to be alienating a fair amount of Tesla fanatics. As a result, I think Tesla's dominance of the market is ending, but Tesla still has too big of a presence in the market for it to be "over."
Personal experience: I own a Model S and while it is exactly what I wanted/needed at the time (fun car to drive with long EV range), the build quality (paint, cheap interior, etc.) is hard to ignore. I plan to trade it in when I buy the Hummer but I've also looked at other EVs comparable to the Model S (Audi e-tron GT and Porsche Taycan) as alternatives if circumstances change. At current prices, I'd buy either of those before I would buy a new Model S, which I believe is overpriced after recent price hikes. The biggest issue with those EVs is range, but I fully expect both will solve for range before I would be in the market for one and well before Tesla solves for its quality issues.