Software hasn't become easier to develop
1. A lot of the new applications are fine for demoing, but don’t meet the requirements of a commercial product (in the pre-2.0 world we called these “toy programs”), so they’re relatively easy to develop. (I think it’s wonderful that these things are being created; let’s just not kid ourselves about what they are and are not.)
2. The fact that large numbers of applications are now being created makes people assume that this is because software development has become easier. I would argue that while there is indeed a case of lowered barriers to entry, the particular barriers are not software development. Specifically:
2(a). In the past, a user needed to have a computer where s/he could install something, and then be willing and able to go through an (often arduous) installation process. Now, to use an application, just type in the application’s URL, or, even easier, just click on a link. So there is a lowered barrier to becoming a potential user for an application, resulting in a skyrocketing number of potential users, increasing the incentive to create the application.
2(b). In the past, an author had to create an installation package, and then distribute it. Now, to publish an application, just put it on your site (which is now dirt cheap to host). So there is a lowered barrier to becoming a potential author, resulting in a skyrocketing of their numbers as well. That is, publishing (not developing) software has become so much easier.
Those of you who are programmers, feel free to comment. Just don’t say anything like “Ruby on Rails is wonderful” unless you can argue why it’s so much better than what’s been around for a long time (please compare against something with high productivity, not something like JEE).