Battery prices are expected to reduce by 50% in 3 to 5 years...and again by 50% in another 3-5 year period after that.

Need to do your homework...I paid more for a similar sized system, and it was cheaper than most other contractors (including rebates). If you could get 2 kW system for $2000, everyone would have one!

Two things to check on this article... the cost of the PV system is usually higher, the generation may be lower....and the utility charges you a monthly fee as you are required to be hooked up to the grid and take electricity from the grid (if you generate more than you use...you get a credit for difference of generation vs. use....which is usually pennies/kWh...way below what you pay to use electricity). So this calculation is overly optimistic.
Note also, expected monthly fees for PV customers are to increase as evidenced by recent applications by utilities to regulatory agencies. PV savings are a moving target.

San Diego offers Electric Vehicle time-of-us rates at 1/2 that rate.