For most successful branded communities, the brand needs to produce a product or service it's customers spend much of their time or money using.
Branded communities exist because we feel a connection to others that purchase the same product/service. You don't feel a connection with people that purchase the same toilet paper as you. Most failed branded communities had no business trying to create a community in the first place.
This isn't to say you're doomed if you're not selling sports cars. You can create something bigger than your brand. Red Bull do a great job building communities around extreme sports rather than fizzy energy drinks.
You can use this information scientifically. Estimate what % of your target audience's time or money they spend using your product/service. If the score is low, perhaps less than 15% to 20%, you may want to rethink your community effort. Or you can copy Red Bull and make something much bigger than what you sell.
The lower the score the harder it is to create a community.