I think that whilst it was built into the original price of the car there are huge number of improvements in spec in the vehicles that have had no price increase, for instance AP2.0 hardware. The SC network is not something that you could expect Tesla to continue providing free forever. The other thing to consider is that they're still providing 400 kwh for free, that's a reasonable chunk of free k's per year, with a growing global fleet the balance sheet liability would have been huge leaving it as 'free unlimited forever'.
Personally I think this is one huge way of saying thank you to the original purchasers, you helped pay for the company to get to where it is an establish this amazing asset, here's a perk for life. With regards to $0.35 per kWh, I think the exact point is that it is supposed to be that it is more expensive than home, these chargers are very expensive to establish and maintain. I also doubt the power itself is cheaper considering the huge draw on the grid. Power packs will help with this but they're not cheap either. My green power through Powershop costs slightly more than this regardless, so it is same same for me. Overall, it is still significantly cheaper than fueling a similar standard of vehicle to go a similar distance.
You should see the S and X becoming cheaper with batteries but ultimately they're still providing a few thousand dollars worth of included kilometres in these vehicles for a 15 year life of vehicle.