Why Electronic Goods Cost of Price Decreases as u go on?????

I the law of supply and demand. There are more supplies of electronic gadgets such as cellphones that it gets cheaper every year. The demand is also getting bigger that it is able to spread its fixed cost that results in cheaper prices. Old models also becomes cheaper because, they are simply old and has to be faced out. Competition also is becoming stiff and pricing is a matter of strategy. So it is always advantageous to have many competitors or brands of cellphones for it to become cheaper and cheaper.