I think that's a common impression. Interestingly, while there are still a lot of questions marks around what makes someone predisposed to addiction, the few things we do know tend to run counter to the idea that people dealing with addiction are overly sensitive to feelings of reward and pleasure. Or that being less sensitive would make someone more resistant.

One of the most well studied genetic risk factors for addiction vulnerability is the DRD2 gene, which encodes the dopamine receptor D_2. People who are particularly vulnerable to addiction commonly have a deficiency here, meaning getting bored very easily and feeling under stimulated/rewarded by typical things is in part what makes riskier sources of pleasure (i.e. drugs) so appealing.

Disclaimer: Not a medical professional, just like reading about addiction and genetics.