Browsers have advanced, servers more capable, networks faster, and we had to contend with that nasty Y2K issue. The browser-based applications have become more robust and easier to use. Add to that a certain amount of conditioning from our five or so years of Internet use and we appear ready to embrace this new paradigm. As with any new technology, early entry comes with a cost. Right now the technology re-invents itself every six months or so and standards are no where to be found.
Skilled resources are next to impossible to find.
Rapid development tools are scarce. For many companies, waiting for standards to emerge and tools to evolve is not an option. Your users and managers need new applications developed and deployed. It may make sense to continue using these platforms. If your environment does not fit into this scenario, then you probably need to look at Browser-Based development and deployment, but what technology do you use.