The whole concept of free wifi is a great way of getting people on the net. Unfortunately, many attempts are made by greedy corporations to stifle free wifi so they can provide services of their own.
In a perfect world free wifi would be available everywhere. Think of all the companies that would go out of business though (cable companies, phone companies, cell phone companies (people would switch to ip type cell phones)). It is a catch 22 and you will start seeing battles go on in the comming years over the offering of free wifi because of this.