When we make large purchases from HP, Dell, Microsoft, you're damn right we negotiate the rates and get discounts. If you're making a purchase that is a large percentage of your budget, you'd be stupid to not try.
When you're buying one laptop, of course not. You're talking a $3000 purchase vs a $40,000+ purchase. You negotiate on cars, because getting a thousand or two off is a huge deal for a lot of people.
The "No haggle" thing that Tesla is doing works fine for their $60,000-$120,000 cars. People spending that kind of cash on a car are probably not going to bat an eye at an extra thousand or two. Anybody spending that much money on a car isn't buying it because they have a limited budget, and are not trying to maximize their value.
I don't think it's going to work as well on their lower priced cars. People who don't have a $50-60k budget for a car don't have tons of money to throw around.