For a typical home inspection, its questionable if you would be able to make enough additional money to pay for the camera. Sure people like the "gosh" aspect of it, but the reality is you are competing with other individuals, and as much as we all hate to say so, price.

If you have a real burning desire to get an IR camera, I would try to market energy surveys. Even then, its questionable if you will get enough work to justify the cost. It all depends where you are using it and how educated the consumer is about the benefits.

Its just another tool we can put on our belts. A great tool for sure, but so are sewer pipe borescopes, blower doors, moisture meters, HVAC gauges, electricians tools, etc......
You have to get return on investment to justify the cost.

As far as commercial applications. In my neck of the woods, that business is already pretty much been staked out.