You cannot discuss the viability of an electric car unless and until you include in the discussion:
1. The life span of the battery under real world conditions
2. Cost of replacement of that battery
3. Cost of disposal/recycling of that battery
Of course, if government $ub$idy is involved, you may ignore the content of this post.
The major problem with lithium batteries longevity has been the anode deterioration over time. If this solves that problem, then 1,2 and 3 are no longer a factor..........