Of course, there is. But making good money out of a plugin is not the easiest.
Plugins are more like small programs designed to fix specific problems.
The following are a couple of points in building a plugin-driven business.
You need to find the right problem to solve using a plugin
It doesn’t have to be something original or never addressed before. It just needs to have a market/demand for it.
You need to nail it
WordPress has more than 70k plugins out there in the wild.
Competition is high, and copycats are pretty fast to release replicas of interesting ideas and successful plugins.
The plugin needs to be top-notch to secure a good spot on the market. And make things hard for anyone trying to copy you.
This means it needs to fix the problem and have an easy-to-use user interface with uncomplicated settings, preferably well-documented and extensible (hooks and API).
The more complete the plugin is, the better.
Have a stellar support
Support is a keystone to any good product out there.
Have friendly, problem-solving support team, and make sure that all requests a processed the fastest possible.
You need to market it in the best way possible
Package it.
Make it look and sound good.
Put it on the right marketplace (if you choose to go that road).
Or hit hard to build a name using ads and SEO.
Like anything for sale on the Internet, a WordPress plugin must convince its prospect that it fixes the problem they are facing.