The most popular application on the PC is the browser. The main reason behind this is that it supports true standards, which are not inter-dependent to each other. That way a consistent cross platform implementation can be achieved. In fact, the first browser was written on the Next platform using Objective-C. Internet protocols for Email are popular for the same reason. If scheduling protocols were open, we would see a lot more people using online calendars.
More people means more revenue for companies.
One of the complexities of client-server projects was that business logic and the remote plumbing, was tied together in one standard. This was one of the reasons for failure. One reason for Perl CGI scripts became so popular was that the web server CGI mechanism handled the remote plumbing and the business logic was handled in the Perl scripts. Just separating the two earlier coupled standard into different standards, made web client server a lot simpler and the success rates for projects went up significantly. In the next few years, millions of new devices will come in the market.