With the ubiquity of broadband across the world, and North America in particular, new software models are able to flourish.
The old software delivery methods had many problems. Before the Internet, or in some cases even with slow Internet connections, you had to go to a brick and mortar store or have the software delivered to you on some type of physical media. It was just easier and quicker than letting your computer download huge files. In the very old school days, if your Internet connection was via the phone lines, you could be disconnected and you'd have to start your download all over again. Some "smarter" download programs could resume where the download left off, but even so the frustration level was just not worth it.