Different dapps will have different use cases and need to look at them individually e.g., Graphite built on Blockstack provides a decentralized G-Suite. That provides utility to some users and that utility is very different from an app like Stealthy.
There are many problems, ranging from infrastructure issues to UX problems to user education, that need to be solved before we can expect broader adoption of dapps.
I'm not familiar with Rinkeby etc so can't really comment. Thanks!