Sure, but there is more than one way to say it:

"I live in the mountains of Virginia and this will never work here with the snow, therefore it's crap, therefore it will fail!!!!"

OR

"It's going to be really hard for them to solve the problem of heavy snow. I wonder if they'll use <something interesting we can all learn about> or <something else>. I wonder if they've teamed up with <who knows> to research <something interesting>. I think the best approach would be x,y,z and I read the Google are using a,b,c".

etc.

I mean, we're talking about a multi-billon dollar company trying to push forward - OF COURSE there are tons of hard parts. Pointing them out it not useful - thinking about (and working on) how to solve them is what HN should be about.

"I wonder if Elon will go down path A...." "Interesting that the battery is now x, this is probably a result of Y technology they developed last year." Etc. I don't find it hard to discuss a topic in a positive light at all.

Time we spend bickering about whether electric cars are ready is time not spent talking about the new grid, the new architecture, the new social organization that will form around these (to me obviously) imminent technologies.

I don't think "how it could succeed" is less interesting than "how it could fail". And if I expect something to succeed, frankly the failure speculation starts to get a bit boring.

It's a bit personal for me because I am pursuing a high-setback business model in my startup and so people always want to talk about the looming dangers they see. It starts to get boring, because I expect a certain number of failures, and I intend to work through them. What's interesting to mr is whether the first principles analysis is right, and how the plan looks from a Zen perspective... Not is everything right, but am I applying pressure in the right place today given the conditions.