If it were that easy to run a business in that market, the original probably wouldn't have went under. Companies go out of business for a number of reasons, but I'd bet on the initial founders who had the vision to create the product and have experience in that market over someone who saw free code online and decided to have a go of it. The reason we almost never see it happen (at least successfully) is that there's almost no barrier to entry (anyone else could pick up the same code) and that it's not an easy market (the original company went out of business).