For info, winrar definitely sell, but not to the average user, to big company!
Explanation: Using a program past its free licensing could hurt the judicial standing of a company and thus, to remove any potential judiciary mishap, Winrar license is brought by them.
The reason why the free license doesn't expire is due to winrar company wanting to use it as a promotional through the user to their company.
People prefer to use what they're used to after all.