Edison brought different inventions together and managed to design a working system. Without him, we would have had to wait a few more years to get electric light out of the labs. Indeed, there were a few working light bulbs before Edison's (e.g. the british Swan bulbs) but none was commercially available.
People look to much to the inventor and too little to the entrepreneur. Inventing is the easy part. Taking the invention to the market is the hard part.
