Your ability to make money from P2P is obvious. Nothing here should have been a surpriseapplications are simply applications, no matter what technology is used. The economics of P2P systems over multi-tier or server systems is just a matter of moving the costs from the server to the end user. The more computing capacity and bandwidth you require, the more money a P2P system can save. Larger computing capacities, higher levels of customization, faster response times, collaboration, and others P2P attributes can increase the net worth of your application.
Will you be successful? That's a very different question. We're just in the early adopter stage and in the infancy of the P2P paradigm. The success of JXTA looks good, and being an early adopter has its advantages. You can't make money unless you spend money (or at least your time).