Interesting calculations. I'm going to suggest that they may be weighted worst case for the EV though. I think it's very unlikely that you're going to see 100% of the fleet need battery replacement at 100,000 miles. What nobody knows for sure is what that number will actually be, but my gut tells me it'll probably be somewhere between 150,000 to 300,000 miles typically. But let's ignore that for a minute. The other assumption you used was 20K for the 85 kWh battery pack in the Tesla. But the Tesla is the luxury car of the EVs. I'd like to offer some other numbers (For my Honda Fit EV). Now, my car is a lease only, but I think the Leaf owners can comment that I think the Leaf will be pretty close. The Honda Fit EV has a 19 kWh battery. Let's assume for argument's sake that we prorate the cost of replacement based on the capacity, so $4470 @ 100,000 miles instead of $20,000. I'll still use the 100,000 mile figure even though I think it's way too conservative. I'm also going to work the calculations assuming $0.12/kWh which is what I pay. I've been seeing 100 miles in the summer and 50 miles in the winter, so I'll assume 75 miles from the 19 kWh battery, even though it's probably better than that (winter isn't 6 months, but we'll assume it is).
100,000 miles: electricity==$3040, battery replacement==$4470, total==$7510/100000 or $0.08/mile
150,000 miles: electricity==$4560, battery replacement==$4470, total==$9030/150000 or $0.06/mile
an ICE car assuming 30 mpg @ $3.00/gallon here in the US right now:
100,000 miles: gas==$10,000, oil changes==$1,000 regular 30/60/90 inspections==$1,000 total==$12000 or $0.12/mile
So, assuming the battery pack cost is proportional, a small EV like the Leaf or the Fit EV is cheaper to operate than the ICE car even assuming 100,000 mile battery pack replacement. But it's probably not even that bad, because as someone else pointed out, once EVs are popular there will almost certainly be shops that will replace bad cells in your pack for a nominal fee. If we assume that for half the cost of the battery pack we can get the car to make it to 250,000 miles (which I think it will probably make without pack servicing) then we see numbers more like:
250,000 miles: electricity==$7600, battery servicing==$2235, total==$9835/250000 or $0.04/mile.
I don't think that's overly optimistic, but it's certainly not pessimistic. I think the ICE numbers are overly optimistic - I don't think many ICE cars make 100,000 miles with only $2,000 of scheduled and unscheduled maintenance, but even if we go with those numbers, a smaller EV is substantially cheaper to operate than a comparable ICE car. I also think that if you rework your numbers to compare the realistic cost of operating a BMW M5 versus the Tesla, it will be a lot closer than your numbers initially indicate. I'd actually expect the Tesla to be moderately cheaper than the BMW when you figure in all the maintenance costs on the M5...
The thing that still makes EV expensive is the initial cost. Right now the small EVs are probably carrying $10,000 to $15,000 extra cost over the ICE version of the car, so if you add that into the equation for the Fit EV it brings the price up to around $0.18/mile which IS more expensive than the ICE car. If we can see manufacturers get the initial price down to be more in line with the ICE cars, then I think the EV can easily be price competitive.
In closing, I'm glad you worked out some hard numbers instead of the regular hand waving that's so typical on Slashdot, but I hope you'll consider that your equations might have been a bit skewed and that the reality is that even with EVs being brand new on the road, the operating costs are more than competitive with ICE, and hopefully we'll see initial prices drop to make them overall competitive with ICE cars.
BTW, the Honda Fit EV is a great car and I'm sorry that Honda doesn't seem to want to compete in the EV market (hydrogen is dumb, I think). I'm anxiously waiting to see what the Tesla Model 3 ends up looking like: if it's competitive with the BMW 3 series for $45K or so, I'm planning on buying one.