OK. With all your corrections, the cost goes up to say $5.
Factor in inflation of electricity prices and your savings goes to over $300!!!!!!!!! Still a deal!
There are places where CFL lamps can be useful. There are many other places where they are not suitable. Incandescent lamps can be dimmed anywhere from full on to barely visible, without hum or flicker, and the change in color temperature when dimmed is well-suited to mood lighting. I have yet to find a dimmable fluorescent that really worked well below about 1/3 brightness. Further, incandescent bulbs work well in a wide range of temperature conditions, and are inherently non-flammable. Although incandescent bulbs may start fires if they are placed in fixtures that can't dissipate the heat they generate, they are very unlikely to fail in such fashion as to generate unexpected amounts of heat. By contrast, fluorescent lamps are made with inherently-flammable electronics. Although the materials are manufactured with flame-retardants, it is possible for the electronics to malfunction in such a way as to generate a lot of heat for a sustained period of time, cooking out the flame-retardants until they are no longer sufficient to prevent ignition.