No.   Once you purchase content you have the rights to the content you purchased in perpetuity.   However as iRacing officially licenses all of the content in the sim, there is a chance iRacing could lose a license to distribute a certain content or property. That means you will still have access to that content but iRacing will no longer be able to sell it to new members or to actively market it.   Because of that, a property could conceivably get phased out of active racing although you would still be able to test and time trial with the property.   We hope we never lose a property but it is possible.     Please also keep in mind that all of the iRacing licenses are long term in nature or are in perpetuity.