The only question left will be mainstream acceptance??
No, the only question left will be economic. Cars costing > $ 70,000 are not for middle income families. Middle (and low) income families make up the vast majority of the U.S. population.
Tesla offers unique differentiators in their product that may or may not be superior to competitor technologies but command a premium price - not unlike many Apple products.
Loaded out Lenovo or HP laptop? low to mid $1000 range. Comparable specs on a 15" Retina MacBook Pro? Mid $2000's. Differentiators - OSX, higher resolution IPS display, gorgeous unibody aluminum construction, tighter ecosystem between computer & mobile device, unparalleled retail sales & support experience through apple stores, SSD faster than spinny hard drive, better battery life. I unashamedly own one. I occasionally ask myself why.
The $1300 Lenovo with 16gb ram, Nvidia 750 discreet video, quad core i7 cpu, and Windows 8.1 will do everything you need in a laptop and 5x more. You just aren't getting those rMBP differentiators. If they are worth an additional $1000, go for it.
A completely loaded Chevy Malibu gets you a four door sedan with turbocharged engine, full leather interior and tons of options for under $31,000. It will comfortably carry you back and forth to work for less than half the cost of the Tesla, it has more than twice the range, refilling it with energy takes five minutes, and while it is using petrochemical fuel, the Teslas - lets not kid ourselves here - are using electricity overwhelmingly generated by dirty coal fired electric plants.
No one is pretending the Lenovo Y510P laptop is a loaded rMBP, or the Chevy Malibu is the equivalent of a Tesla Model S. But the point is this - the high end Apple laptop & 27" desktop products, along with Tesla's vehicles, are - so long as they occupy their current pricing strata - going to be luxury items that a very narrow percentage of the U.S. market can afford. They will accordingly occupy a small percentage of market share.
Apple and Tesla are both destined to exist as luxury brands that will always be around, always appeal to a certain well-heeled discriminating consumer, but are fated to occupy very narrow market share. Like Rolex, Gucci, Coach hand bags, those red-soled Louboutin heels your wife / girlfriend / both have had their eyes on - they are priced outside the realm of sanity for all but enthusiasts, the foolhardy, or the very well heeled.
If Elon can scale manufacturing to produce a vehicle similar to the Nissan Leaf, improve range to 200+ miles between charges, ++ plus the quality and options a little, and get the price down into the $25-35k range while still making an acceptable profit, Tesla might have something to talk about. Until such time, Teslas sales are going to exist in a range that to companies like Ford, GM, and whatever Chrysler/Fiat is calling themselves this week - is a rounding error on just one of their models' annual sales.
Tesla sold 20some thousands Model S sedans last year? Ford sold, on average, over 50,000 F-150 pickups PER MONTH in 2013. ONE manufacturer. ONE MODEL.
I love Tesla, I admire Elon, but the numbers are just wrong for most of America.