Why does every company copy from Apple?

I grew up with computers since childhood and I always encounter this strange thing. Almost all companies copy from Apple. When people talk about Apple they say it is a cool and cutting edge company unlike others. Although I accept they are overpriced but their products are comparable to none. First Apple incorporated GUI in their computers and Microsoft stole the idea and sold their software to every other computer manufacturers. Apple was the ones who actually first invented personal computers. If Microsoft had not bought DOS from TIm Paterson from Seattle Computing, IBM would have never competed with Apple. When we get to new products, Apple first brought the iPod and all companies like Sony, Samsung, LG, Zune, Creative and so on started to copy and entered their market. Wen it comes to phone, after Apple released iPhone many companies like Sony, Samsung, HTC, Blackberry and so on copied and entered the phone market. Now I see a lot of tablet pads from Samsung, Dell, LG, T-Mobile, Motorola, Toshiba, Acer, Asus compete with the legendary iPad. Why are all these companies copying instead of pursuing an innovative business or technological strategy.