Well, I've long (nearly since Tesla founding) maintained that the biggest issue with Tesla would ultimately be the production scaling ability. Scaling efficiency reduces cost and ultimately leads to a wider market. Further, I was always watching the funding aspect, particularly the subsidy aspect and profit. I long though of shorting, but hey... I didn't.
That said, while I agree with your sentiment regarding loyalty to a degree, I don't agree to the extent. There are a goodly number of people that buy a brand. I also think there are car people and people that buy cars. It's pretty clear Tesla created a bit of a hybrid, people that buy Teslas. I think there was a great possibility to get into that market with a lower cost entry.
Ultimately, I agree with your one trick pony assessment, but I think the production scaling and lack of a lower cost entry Tesla was the cause. Oddly, I really wanted Tesla to succeed, still want it to. I know the car helped change the market forever. Those are good things. The back end dealing with dead lithium ion batteries and mining for new ones is a bad one, but that's not a Tesla only issue.