Apple would want to pay $75B for the book value of Tesla? Why would they need the Tesla brand, considering they've already got a perfectly good brand? Do they want their former employees back that badly? Are they looking to bring Musk on as CEO of Apple? Why not just buy Oldsmobile from GM? This makes no sense to me.
Well, there are a couple of reasons to acquire Tesla in 2016/2017 that do make sense IMO. First, with Tesla's gigafactory Apple could instantly champion battery world market which Samsung and LG, direct competitors to Apple, are already doing good business in. By acquiring Tesla, Apple would enter residential energy storage markets, too. Furthermore, Tesla has a compelling and user-friendly charging network around the world which future Apple cars could use. That was a lot of work for Tesla to get the permissions, find the right spots, etc. . Tesla also has the stores and service centers built up with competent and motivated staff which Apple would need to build up themselves otherwise. Tesla has also the experience to sell and roll-out EVs (dealing with regulations, fleet customers, etc.) in a considerable amount of world markets which Apple would have to build up themselves, too. So, in these terms, time is the crucial factor. Through an acquisition of Tesla, Apple would simply buy time, to conquer EV markets around the world in a short time span, like a sudden earthquake and tsunami. Otherwise, the necessariy incremental steps in Apple EV development would give the old players (GM, Daimler, BMW, VW, Toyota) time to adapt.
Now, why would Tesla sell? I think it comes down to cash. Tesla is the fastest growing automobile company in the world but I guess it will need a lot more cash to keep up the pace of that growth: Think European Factory for Model 3, Think Chinese Factory for Model 3, Think GF 2, what have you. They need capital to keep up this fast growth. Apple is able to deliver exactly that. To sum up, having the ultimate goal of Tesla in mind, namely to accelerate the advent of electric vehicles, Apple acquiring Tesla in 2016/2017 is a superb idea IMHO.