These analysts are typically guys who are not automotive analysts, but technology analysts. They have large misconceptions about the automotive industry and how quickly can the technology change. The transition from ICE to electric engines is a huge one with a number of technology and production issues to still be resolved. Reasonable analyses I've seen from automotive industry guys have hybrids jumping to 25-35% of vehicle sales by 2030, with full electrics staying below 5%. 50% by mid-2020's or even 2030's is a pipe dream.
To put it simply, Tesla's Gigafactory will take 5 years to build (2015 - 2020 for full capacity) at a cost of $5 billion and will supply batteries for 1.5 million cars. European vehicle sales (passenger cars and light commerial vehicles, which includes SUV's) are in the 10 - 15 million per year range, US are 15 - 20 million per year range. So to supply this volume of vehicles (50% of 25 - 35 million per year), you would need 10 Gigafactories, with building to start by early 2020's. I haven't seen any plans for this to happen, so the battery supply will not be there to build these vehicles. Infrastructure is the second issue. It takes time to build out the network of charging stations and there are no widespread plans to do this either.
So, all these plans and commitments are meaningless unless they are accompanied by major investments into battery and electric component production and infrastructure investment. When that happens, I'll believe that electric cars will have meaningful sales.