Without SC's, I would not have a Tesla. Period! For the past five years I've averaged 7000 mi/yr on the Leaf. Somehow I managed to put 12,000 mi on the Tesla in the first 7 months of ownership! Some people just won't purchase until there are SC's nearby or for their chosen route. The lack of stations in middle America is certainly impacting a few decisions.
Why has it taken so long? It's a lot of work. However, let's all crowd-source and help Tesla move faster. If you have a route that needs a SC, then send specific addresses, businesses, and contacts to Tesla. Better yet, talk directly to hotel and restaurant business owners who might benefit from a SC. I've done this in a number of locations and, although I haven't seen anything yet, it's still early. As batteries degrade, more Tesla's are purchased, and future models get SC-capability, the density of stations will have to increase. The spacing will likely decrease to 50-100 miles all across the network. We're already seeing fill in where there are high numbers (SFO, LA, NYC).